Actinic ray-sensitive or radiation-sensitive resin composition and pattern forming method using same

ABSTRACT

An actinic ray-sensitive or radiation-sensitive resin composition includes (A) a resin having at least two of repeating units represented by general formula (1) below and exhibiting increased solubility in an alkali developer when acted on by an acid, and (B) a compound that generates an acid when exposed to actinic rays or radiation. 
     
       
         
         
             
             
         
       
     
     In the formula, each of R, A, R 0 , Z, L and n represents the same as defined in the claims and in the specification.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/078,028, filed Jul. 3, 2008.

This application is based upon and claims the benefit of priority fromprior Japanese Patent Applications No. 2008-171872, filed Jun. 30, 2008;and No. 2009-141027, filed Jun. 12, 2009, the entire contents of both ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an actinic ray-sensitive orradiation-sensitive resin composition that undergoes a reaction whenexposed to actinic rays or radiation thereby changing its properties,and also relates to a method of forming a pattern therewith. Moreparticularly, the present invention relates to an actinic ray-sensitiveor radiation-sensitive resin composition for use in a production of asemiconductor such as an IC and a production of a circuit board for athermal head, a liquid crystal and the like; for use in otherphotofabrication processes; for use in a production of a lithographicprinting plate; and for use as an acid-setting composition; and alsorelates to a method of forming a pattern therewith.

In the present invention, the terms “actinic rays” and “radiation” mean,for example, a mercury lamp bright line spectrum, far ultraviolet raysrepresented by an excimer laser, extreme ultraviolet rays, X-rays,electron beams and the like. In the present invention, the term “light”means actinic rays or radiation.

2. Description of the Related Art

A chemical amplification resist is capable of, upon exposure to farultraviolet rays or other radiation, generating an acid at the exposedarea. A reaction catalyzed by the generated acid allow the solubility ofthe exposed area in a developer to be different from that of thenon-exposed area. The difference in the solubility between those areasmakes it possible to attain pattern formation on a substrate.

In using a KrF excimer laser as an exposure light source, a resin whosefundamental skeleton consists of a poly(hydroxystyrene) exhibiting a lowabsorption mainly in the region of 248 nm is employed as a majorcomponent. Accordingly, favorable pattern with high sensitivity and highresolving power can be formed. Thus, a system superior to theconventional naphthoquinone diazide/novolak resin system has beenrealized.

On the other hand, in using a light source of a further shorterwavelength, for example, an ArF excimer laser (193 nm) as an exposurelight source, the above-mentioned chemical amplification system has notbeen satisfactory because the compounds having an aromatic groupinherently exhibit a sharp absorption in the region around 193 nm.

Therefore, various resists for an ArF excimer laser containing analicyclic hydrocarbon structure have been developed. However, thecurrent situation is that it is extremely difficult to discover anappropriate combination among an employed resin, a photoacid generator,an additive and a solvent, etc., from the viewpoint of the comprehensiveperformance of a resist. Further, in the formation of a fine patternwhose line width is, for example, 65 nm or less, it has been demanded toimprove line edge roughness performance of line-pattern and resolvingpower.

It has been found that the resolving power and line edge roughnessperformance can be improved by incorporation of a repeating unit havinga specific lactone structure in a resin with the above alicyclichydrocarbon structure. For example, Jpn. Pat. Appln. KOKAI PublicationNo. (hereinafter referred to as JP-A-) 2005-352466 and JP-A-2004-210917describe resist compositions containing resins having specific lactonerepeating units in which a spacer is introduced between the polymerprincipal chain and the lactone skeleton. Further, JP-A-2008-31298describes that not only the resolving power and line edge roughness butalso the dependency on density distribution and exposure margin can beimproved by use of a resist composition containing a resin having aspecific lactone repeating unit in which a similar spacer isincorporated.

Still further, JP-A-2003-5375, JP-A-2003-255537 and JP-A-2003-252933disclose compositions characterized by containing resins obtained bycopolymerization of two or more types of lactone monomers.

However, in view of the most recent developments in which use is made ofa line width of 45 nm or less and to which a liquid immersion process isapplied, it is demanded to raise the level of relevant technology.Accordingly, the above-mentioned prior art is not always satisfactoryand the current situation is that deficiency is encountered not only inthe Line Width Roughness (LWR) but also in the exposure latitude andMask Enhancement Error Factor (MEEF).

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide an actinicray-sensitive or radiation-sensitive resin composition with improvedLWR, exposure latitude and MEEF, being suitable for use in a liquidimmersion process for a line width of 45 nm or less, and to provide amethod of forming a pattern therewith.

Some aspects of the present invention will be described below:

[1] An actinic ray-sensitive or radiation-sensitive resin compositioncharacterized by comprising:

(A) a resin having at least two of repeating units represented bygeneral formula (1) below and exhibiting increased solubility in analkali developer when acted on by an acid; and

(B) a compound that generates an acid when exposed to actinic rays orradiation;

wherein:

R represents a hydrogen atom or an optionally substituted alkyl group;

A represents:

R₀, each independently in the presence of two or more groups, representsan optionally substituted alkylene group, an optionally substitutedcycloalkylene group or a combination thereof, with the proviso that analkylene group having two or more carbon atoms is excluded when Lrepresents a butyrolactone;

Z, each independently in the presence of two or more groups, representsan ether bond, an ester bond, an amido bond, a urethane bond or a ureabond;

L represents a substituent with a lactone structure; and

n represents the number of repetitions and is an integer of 1 to 5.

[2] The composition according to [1], characterized in that the resin(A) has at least one of repeating units represented by general formula(1-1) below as the repeating unit represented by the general formula(1);

wherein:

R, A, R₀, Z and n are as defined above with respect to the generalformula (1) of [1];

R₁, each independently in the presence of two or more groups, representsan optionally substituted alkyl group, an optionally substitutedcycloalkyl group, an optionally substituted ester group, a cyano group,a hydroxy group or an alkoxy group, and provided that two or more R₁sare present, two thereof may be bonded to each other to form a ring;

X represents an alkylene group, an oxygen atom or a sulfur atom; and

m represents the number of substituents and is an integer of 0 to 5.

[3] The composition according to [2], characterized in that the resin(A) has at least two of the repeating units represented by the generalformula (1-1).[4] The composition according to any one of [1] to [3], characterized inthat each of the at least two of the repeating units represented by thegeneral formula (1) has different rates of alkali hydrolysis.[5] The composition according to any one of [1] to [4], characterized inthat a glass transition point of the resin (A) is within the range of130° C. to 170° C.[6] The composition according to any one of [1] to [5], characterized inthat the resin (A) has both at least one repeating unit having any ofgroups represented by general formula (2-1) below and at least onerepeating unit having any of groups represented by general formula (2-2)below;

wherein:

in the general formula (2-1),

each of R₂s independently represents an optionally substituted alkylgroup or an optionally substituted monocyclic alkyl group, with theproviso that at least one of the R₂s is an optionally substitutedmonocyclic alkyl group, and provided that when all of the R₂s are alkylgroups, two R₂s are bonded to each other to form a monocyclic alkylgroup; and

in the general formula (2-2),

each of R₃s independently represents an optionally substituted alkylgroup or an optionally substituted polycyclic alkyl group, with theproviso that at least one of the R₃s is an optionally substitutedpolycyclic alkyl group, and provided that when all of the R₃s areoptionally substituted alkyl groups, two R₃s are bonded to each other toform a polycyclic alkyl group.

[7] The composition according to any one of [1] to [6], characterized bycontaining any of compounds represented by general formula (I) below asthe compound (B);

wherein X⁺ represents a sulfonium or an iodonium, and R represents ahydrogen atom or a substituent having one or more carbon atoms.

[8] The composition according to any one of [1] to [7], characterized byfurther comprising (C) a hydrophobic resin.[9] A method of forming a pattern, characterized by comprising:

forming the composition according to any one of [1] to [8] into a film,

exposing the obtained film, and

developing the exposed film.

The present invention has made it feasible to provide an actinicray-sensitive or radiation-sensitive resin composition with improvedLWR, exposure latitude and MEEF, being suitable for use in a liquidimmersion process for a line width of 45 nm or less and to provide amethod of forming a pattern therewith.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described below.

Note that, with respect to the expression of a group (or an atomicgroup) used in this specification, the expression without explicitlyreferring to whether the group is substituted or unsubstitutedencompasses not only groups with no substituents but also groups havingone or more substituents. For example, the expression “alkyl group”encompasses not only alkyl groups having no substituents (viz.unsubstituted alkyl groups) but also alkyl groups having one or moresubstituents (viz. substituted alkyl groups).

Also note that, in this specification, mass ratio is equal to weightratio.

[1] resin (A) whose solubility in an alkali developer is increased bythe action of an acid:

The resin (A) contained in the actinic ray-sensitive orradiation-sensitive resin composition according to the present inventionhas at least two of the repeating units represented by the followinggeneral formula (1).

In the general formula (1),

R represents a hydrogen atom or an optionally substituted alkyl group.

A represents:

R₀, each independently in the presence of two or more groups, representsan optionally substituted alkylene group, an optionally substitutedcycloalkylene group or a combination thereof, with the proviso that achain alkylene group having two or more carbon atoms is excluded when Lrepresents a butyrolactone.

Z, each independently in the presence of two or more groups, representsan ether bond, an ester bond, an amido bond, a urethane bond or a ureabond.

L represents a substituent with a lactone structure, and

n represents the number of repetitions and is an integer of 1 to 5.

A further detailed description will be made with respect to the generalformula (1).

The alkyl group represented by R is preferably an alkyl group having 1to 4 carbon atoms, more preferably a methyl group or an ethyl group, andmost preferably a methyl group. As substituents on R, a halogen atomsuch as a fluorine atom, a chlorine atom or a bromine atom, a mercaptogroup, a hydroxy group, an alkoxy group such as a methoxy group, anethoxy group, an isopropoxy group, a t-butoxy group or a benzyloxygroup, an acyl group such as an acetyl group or a propionyl group, andan acetoxy group.

The group represented by R₀ is any of a chain alkylene group, acycloalkylene group and a combination thereof, with the proviso that achain alkylene group having two or more carbon atoms is excluded whenthe group represented by L is a butyrolactone. The chain alkylene groupis preferably a chain alkylene group having 1 to 10 carbon atoms, morepreferably 1 to 5 carbon atoms, for example, a methylene group, anethylene group or a propylene group. The cycloalkylene group ispreferably a cycloalkylene group having 4 to 20 carbon atoms, forexample, a cyclohexylene group, a cyclopentylene group, a norbornylenegroup or an adamantylene group. The chain alkylene groups are preferredfrom the viewpoint of the exertion of the effect of the presentinvention. Of these, the methylene group is particularly preferred. As apossible substituent of the chain or cyclic alkylene group representedby R₀, a hydroxy group, a cyano group, an alkoxy group having 1 to 4carbon atoms, an alkoxycarbonyl group and an acyloxy group can beexemplified.

Z preferably represents an ether bond, an ester bond or a urethane bond,more preferably an ether bond or an ester bond.

n is preferably 1.

The substituents with a lactone structure represented by L are notparticularly limited as long as a lactone structure is containedtherein. However, lactone structures of a 5- to 7-membered ring arepreferred, and particularly preferred are those resulting fromcondensation of lactone structures of a 5- to 7-membered ring with othercyclic structures effected in a fashion to form a bicyclo structure orspiro structure. More preferred is a lactone structure represented byany of general formulae (LC1-1) to (LC1-17) below. The lactonestructures may be directly bonded to the principal chain of the resin.Preferred lactone structures are those of formulae (LC1-1), (LC1-4),(LC1-5), (LC1-6), (LC1-13), (LC1-14), and (LC1-17).

The presence of a substituent Rb₂ on the lactone structure is optional.As a preferred substituent Rb₂, an alkyl group having 1 to 8 carbonatoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy grouphaving 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbonatoms, a carboxyl group, a halogen atom, a hydroxy group, a cyano group,and an acid-decomposable group can be exemplified. Of these, an alkylgroup having 1 to 4 carbon atoms, a cyano group and an acid-decomposablegroup are more preferred. In the formulae, n₂ is an integer of 0 to 4.When n₂ is 2 or greater, the plurality of present substituents Rb₂ maybe identical to or different from each other. Further, the plurality ofpresent substituents Rb₂ may be bonded to each other to form a ring.

As especially preferred lactone repeating units, those represented bythe following general formula (1-1) can be exemplified.

In the general formula (1-1),

R, A, R₀, Z and n are as defined above with respect to the generalformula (1).

R₁, each independently in the presence of two or more groups, representsan optionally substituted alkyl group, an optionally substitutedcycloalkyl group, an optionally substituted ester group, a cyano group,a hydroxy group or an alkoxy group. In the presence of two or more R₁s,two thereof may be bonded to each other to form a ring.

X represents an alkylene group, an oxygen atom or a sulfur atom.

m represents the number of substituents and is an integer of 0 to 5, andpreferably 0 or 1.

A further detailed description will be made with respect to the generalformula (1-1).

The preferred examples of the groups represented by R and R₀ are thesame as mentioned with respect to the general formula (1).

The alkyl group represented by R₁ is preferably an alkyl group having 1to 4 carbon atoms, more preferably a methyl group or an ethyl group, andmost preferably a methyl group. As the cycloalkyl group, a cyclopropylgroup, a cyclobutyl group, a cyclopentyl group and a cyclohexyl groupcan be exemplified. As the ester group, a methoxycarbonyl group, anethoxycarbonyl group, an n-butoxycarbonyl group and a t-butoxycarbonylgroup can be exemplified. As the alkoxy group, an alkoxy group having 1to 4 carbon atoms is preferred. As the substituent therefor, a hydroxygroup, an alkoxy group such as a methoxy group or an ethoxy group, acyano group, and a halogen atom such as a fluorine atom can beexemplified.

R₁ preferably represents a methyl group, a cyano group or analkoxycarbonyl group. Of these, a cyano group is particularly preferred.

As the alkylene group represented by X, a methylene group and anethylene group can be exemplified. X preferably represents an oxygenatom or a methylene group. Of these, a methylene group is particularlypreferred.

When m is 1 or greater, the substitution site of at least one R₁ ispreferably the α-position or β-position of the carbonyl group of thelactone. The substitution at the α-position is especially preferred.

Specific examples of the repeating units having groups with a lactonestructure expressed by the general formula (1) will be shown below,which however in no way limit the scope of the present invention.

In the following specific examples, R represents a hydrogen atom, anoptionally substituted alkyl group or a halogen atom. Preferably, Rrepresents a hydrogen atom, a methyl group, a hydroxymethyl group or anacetoxymethyl group.

Especially preferred specific examples of the repeating unitsrepresented by the general formula (1-1) are as follows.

The effects of the present invention can be fully exerted throughcopolymerization of at least two lactone monomers according to thepresent invention. Although the reasons therefor has not beenelucidated, the use of a single monomer does not ensure full exertion ofthe effects of the present invention.

The monomer combination for the copolymerization is preferably such thatthe lactone monomers corresponding to the repeating units represented bythe general formula (1) are different from each other in the rate ofalkali hydrolysis. Further, it is preferred to select two or more typesfrom the lactone repeating units of the general formula (1) in which nis 1 and make simultaneous use thereof. Preferably, the two or moretypes of lactone repeating units are obtained by copolymerizing amonomer corresponding to a repeating unit having a substituent at theα-position or β-position of the carbonyl group of the lactone incombination with a monomer corresponding to a repeating unit having nosubstituent at both the α-position and the β-position of the carbonylgroup of the lactone. In particular, it is preferred to combine arepeating unit having an ester group or a cyano group at the α-positionor β-position with a repeating unit having no substituent.

As a way to increase the rate of hydrolysis of a lactone repeating unit,introduction of an electron withdrawing group as a substituent of thelactone group (R₁ in general formula [1-1]) can be exemplified. As theelectron withdrawing group, a cyano group, a nitro group, a carboxygroup and an ester group can be exemplified. Preferred electronwithdrawing groups includes a cyano group, a nitro group and an estergroup. Especially preferred electron withdrawing group is a cyano group.The site at which the electron withdrawing group is introduced ispreferably the α-carbon of the carbonyl group of the lactone.

The rate of alkali hydrolysis is that determined by causing a lactonemonomer dissolved in an organic solvent to react with an alkali aqueoussolution and measuring the rate of consumption by means ofhigh-performance liquid chromatography (HPLC). The experimentalprocedure is as follows.

(Measuring Conditions for HPLC) Apparatus: New Shimadzu,

column: Sympack column (ODS),eluate: acetonitrile/buffer=70/30, 1 ml/min,buffer: distilled water/phosphoricacid/triethylamine=1000/1/1, anddetection: 254 nm.

(Preparation of Solution)

(A) Anisole Solution (Internal Standard)

1 g of 2,4-dimethylanisole is placed in a 50 ml measuring flask andmeasured up with acetonitrile.

(B) Lactone Sample Solution

1 mmol of a sample and 2 ml of the anisole solution (A) are placed in a10-ml measuring flask and measured up with acetonitrile.

(Measurement) (1) Reference Measurement

0.3 ml of a sample solution and 2.7 ml of acetonitrile are placed in anHPLC sample tube and measured by HPLC.

(2) Sample Measurement (Reaction with Alkali: Evaluation ofHydrolyzability)

0.3 ml of a sample solution and 1.2 ml of acetonitrile are placed in anHPLC sample tube, and 1.5 ml of a pH-10 standard solution is addedthereto, gently shaken so as to obtain a homogeneous mixture, and thenmeasured by HPLC.

(3) Sample Measurement (Reaction with Water: Evaluation of Stability)

The procedure of the item (2) above is repeated except that water isused in place of the pH-10 standard solution.

An area ratio between that of the monomer and of the internal standardat the beginning of reaction is set as an base quantity (100%), and thearea ratio at each reaction time is divided by the base quantity to givea monomer residual ratio (%). The monomer residual ratio (%) at thelapse of a given time is defined to be the rate of alkali hydrolysis.

Monomer combination in the copolymerization is preferably such that theratio between relative values of the rate of alkali hydrolysisdetermined by the calculation method to be described in the Examplesbelow is 1.5 or more. A more preferred monomer combination is such thatthe ratio is in the range of 2 to 1000.

The resin (A) according to the present invention preferably has a glasstransition point within the range of 130° C. to 170° C., more preferably140° C. to 160° C.

The total content of repeating units represented by the general formula(1) based on all the repeating units of the resin (A) is preferably inthe range of 5 to 65 mol %, more preferably 10 to 60 mol %, and stillmore preferably 15 to 55 mol %. When one of the repeating unitsrepresented by general formula (1) is used in combination with anotherof the repeating units represented by general formula (1), the molarratio between them is preferably in the range of 90/10 to 10/90, morepreferably 80/20 to 20/80, and still more preferably 75/25 to 25/75.

The resin (A) is a resin whose solubility in an alkali developer isincreased by the action of an acid, especially a resin provided at itsprincipal chain or side chain or both thereof with a group that isdecomposable by the action of an acid to generate an alkali-solublegroup (also referred to as an “acid-decomposable group”).

As the alkali-soluble group, a phenolic hydroxy group, a carboxy group,a fluoroalcohol group, a sulfonate group, a sulfonamido group, asulfonylimido group, an (alkylsulfonyl)(alkylcarbonyl)methylene group,an (alkylsulfonyl)(alkylcarbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylenegroup can be exemplified.

As preferred alkali-soluble groups, a carboxy group, a fluoroalcoholgroup (preferably hexafluoroisopropanol) and a sulfonate group can beexemplified.

The acid-decomposable group is preferably a group as obtained bysubstituting the hydrogen atom of any of these alkali-soluble groupswith an acid-eliminable group.

As the acid-eliminable group, groups represented by —C(R₃₆)(R₃₇)(R₃₈),—C(R₃₆)(R₃₇)(OR₃₉) and —C(R₀₁)(R₀₂)(OR₃₉) can be exemplified.

In the formulae, each of R₃₆ to R₃₉ independently represents an alkylgroup, a cycloalkyl group, an aryl group, an aralkyl group or an alkenylgroup. R₃₆ and R₃₇ may be bonded to each other to form a ring.

Each of R₀₁ and R₀₂ independently represents a hydrogen atom, an alkylgroup, a cycloalkyl group, an aryl group, an aralkyl group or an alkenylgroup.

The acid-decomposable group is preferably a cumyl ester group, an enolester group, an acetal ester group, a tertiary alkyl ester group or thelike. Particularly preferred is a tertiary alkyl ester group.

The tertiary alkyl ester group is preferably any of the groupsrepresented by the following general formula.

In general formula (A),

Xa₁ represents a hydrogen atom, a methyl group, a trifluoromethyl groupor a hydroxymethyl group,

T represents a single bond or a bivalent connecting group, and

each of Rx₁ to Rx₃ independently represents an alkyl group (linear orbranched) or a cycloalkyl group (monocyclic or polycyclic),

wherein at least two of Rx₁ to Rx₃ may be bonded to each other to form amonocyclic or polycyclic alkyl group.

As the bivalent connecting group represented by T, an alkylene group, agroup of the formula —COO-Rt-, and a group of the formula —O-Rt- can beexemplified. In the formulae, Rt represents an alkylene group or acycloalkylene group.

T is preferably a single bond or a group of the formula —COO-Rt-. Rt ispreferably an alkylene group having 1 to 5 carbon atoms, more preferablya —CH₂— group or —(CH₂)₃— group.

The alkyl group represented by each of Rx₁ to Rx₃ is preferably onehaving 1 to 4 carbon atoms, such as a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an isobutyl groupor a t-butyl group.

The cycloalkyl group represented by each of Rx₁ to Rx₃ is preferably amonocyclic alkyl group such as a cyclopentyl group or a cyclohexylgroup, or a polycyclic alkyl group such as a norbornyl group, atetracyclodecanyl group, a tetracyclododecanyl group or an adamantylgroup.

The cycloalkyl group formed by bonding of at least two of Rx₁ to Rx₃ ispreferably a monocyclic alkyl group such as a cyclopentyl group or acyclohexyl group, or a polycyclic alkyl group such as a norbornyl group,a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantylgroup.

As the above tertiary alkyl ester group, it is preferred to use eitherany of the groups represented by general formula (2-1) below or any ofthe groups represented by general formula (2-2) below.

In the general formula (2-1), each of R₂s independently represents anoptionally substituted alkyl group or an optionally substitutedmonocyclic alkyl group. At least one of R₂s is an optionally substitutedmonocyclic alkyl group, or provided that all of R₂s are alkyl groups,two thereof are bonded to each other to form a monocyclic alkyl group.

In the general formula (2-2), each of R₃s independently represents anoptionally substituted alkyl group or an optionally substitutedpolycyclic alkyl group. At least one of R₃s is an optionally substitutedpolycyclic alkyl group, or provided that all of R₃s are optionallysubstituted alkyl groups, two thereof are bonded to each other to form apolycyclic alkyl group.

The alkyl group represented by each of R₂ and R₃ is preferably onehaving 1 to 4 carbon atoms, such as a methyl group, an ethyl group, ann-propyl group, an isopropyl group, an n-butyl group, an isobutyl groupor a t-butyl group.

The monocyclic alkyl group represented by R₂ is preferably a cycloalkylgroup having 5 to 8 carbon atoms, such as a cyclopentyl group or acyclohexyl group, more preferably a cyclopentyl group or a cyclohexylgroup.

As the polycyclic alkyl group represented by R₃, a norbornyl group, atetracyclodecanyl group, a tetracyclododecanyl group and an adamantylgroup can be exemplified.

From the viewpoint of enhancing the effects of the present invention, itis preferred to simultaneously use two types of acid-decomposable groupseach represented by the general formulae (2-1) and (2-2).

The content of repeating units having acid-decomposable groups based onall the repeating units of the resin (A) is preferably in the range of20 to 60 mol %, more preferably 25 to 55 mol %.

In particular, when the groups respectively represented by the generalformulae (2-1) and (2-2) are simultaneously used, each thereof iscontained preferably in an amount of 5 to 55 mol % based on all therepeating units.

Specific examples of the repeating units having preferredacid-decomposable groups will be shown below, which however in no waylimit the scope of the present invention.

In the specific examples, each of Rx and X_(a1) represents a hydrogenatom, CH₃, CF₃, or CH₂OH. Each of Rxa and Rxb represents an alkyl grouphaving 1 to 4 carbon atoms, respectively. Z represents a substituentcontaining one or more polar groups. When two or more of Z are present,they are independent from one another. P represents 0 or a positiveinteger.

In particular, the following repeating unit with a polycyclicacid-decomposable group is preferred from the viewpoint of improvingroughness.

In the formula (A-1),

R₃ to R₅ have the same meaning as the corresponding groups of thegeneral formula (A).

R₁₀ represents a substituent containing a polar group. When two or moreR₁₀s are introduced, they may be identical to or different from eachother. As the substituent containing a polar group, a linear or branchedalkyl group or cycloalkyl group having a hydroxyl group, a cyano group,an amino group, an alkylamido group and a sulfonamido group can beexemplified. An alkyl group having a hydroxyl group is preferred. Abranched alkyl group having a hydroxyl group is more preferred. Anespecially preferred branched alkyl group is an isopropyl group.

In the formula, p is an integer of 0 to 15, preferably 0 to 2 and morepreferably 0 or 1.

The repeating units represented by the general formula (A-1) arepreferably those shown below.

Preferably, the resin (A) further contains a repeating unit having ahydroxy group or a cyano group other than that represented by thegeneral formula (1) and (A). The containment of this repeating unitwould realize enhancements of adhesion to substrate and developeraffinity. The repeating unit having a hydroxy group or a cyano group ispreferably a repeating unit having an alicyclic hydrocarbon structuresubstituted with a hydroxy group or a cyano group. Further, therepeating unit having a hydroxy group or a cyano group is preferablyfree from the acid-decomposable group. In the alicyclic hydrocarbonstructure substituted with a hydroxy group or a cyano group, thealicyclic hydrocarbon structure preferably consists of an adamantylgroup, a diamantyl group or a norbornane group. As preferred alicyclichydrocarbon structures substituted with a hydroxy group or a cyanogroup, the partial structures represented by the following generalformulae (VIIa) to (VIId) can be exemplified.

In the general formulae (VIIa) to (VIIc),

each of R₂c to R₄c independently represents a hydrogen atom, a hydroxygroup or a cyano group, with the proviso that at least one of the R₂c toR₄c represents a hydroxy group or a cyano group. Preferably, one or twoof the R₂c to R₄c are hydroxy groups and the remainder is a hydrogenatom. In the general formula (VIIa), more preferably, two of the R₂c toR₄c are hydroxy groups and the remainder is a hydrogen atom.

As the repeating units having any of the partial structures representedby the general formulae (VIIa) to (VIId), those of the following generalformulae (AIIa) to (AIId) can be exemplified.

In the general formulae (AIIa) to (AIId),

R₁c represents a hydrogen atom, a methyl group, a trifluoromethyl groupor a hydroxymethyl group.

R₂c to R₄c have the same meaning as those of the general formulae (VIIa)to (VIIc).

The content of repeating units having an alicyclic hydrocarbon structuresubstituted with a hydroxy group or a cyano group based on all therepeating units of the resin (A) is preferably in the range of 1 to 30mol %, more preferably 3 to 28 mol % and still more preferably 5 to 25mol %.

Specific examples of the repeating units having a hydroxy group or acyano group will be shown below, which however in no way limit the scopeof the present invention.

The resin as the component (A) preferably contain a repeating unithaving an alkali-soluble group. As the alkali-soluble group, a carboxygroup, a sulfonamido group, a sulfonylimido group, a bisulfonylimidogroup and an aliphatic alcohol substituted at its α-position with anelectron-withdrawing group (for example, a hexafluoroisopropanol group)can be exemplified. The possession of a repeating unit having a carboxygroup is more preferred. The incorporation of the repeating unit havingan alkali-soluble group would increase the resolving power in contacthole usage. The repeating unit having an alkali-soluble group ispreferably any of a repeating unit wherein the alkali-soluble group isdirectly bonded to the principal chain of a resin such as a repeatingunit of acrylic acid or methacrylic acid, a repeating unit wherein thealkali-soluble group is bonded via a connecting group to the principalchain of a resin, and a repeating unit wherein the alkali-soluble groupis introduced in a terminal or termini of a polymer chain by the use ofa chain transfer agent or polymerization initiator having thealkali-soluble group in the stage of polymerization. The connectinggroup may have a monocyclic or polycyclic hydrocarbon structure.Especially preferred is the repeating unit of acrylic acid ormethacrylic acid.

The content of the repeating unit having an alkali-soluble group basedon all the repeating units of the resin (A) is preferably equal to orlower than 25 mol %, more preferably equal to or lower than 20 mol %,and still more preferably in the range of 1 to 15 mol %. Specificexamples of the repeating units having an alkali-soluble group will beshown below, which however in no way limit the scope of the presentinvention. In the specific examples, Rx represents H, CH₃, CF₃ or CH₂OH.

It is preferred for the resin (A) for use in the present invention tofurther have a repeating unit that has an alicyclic hydrocarbonstructure having no polar group and does not exhibit any aciddecomposability. Having this repeating unit would reduce the leaching oflow-molecular components from the film into a liquid for liquidimmersion at the time of liquid immersion exposure. As such a repeatingunit, any of the repeating units represented by general formula (4)below can be exemplified.

In the general formula (4), R₅ represents a hydrocarbon group having atleast one cyclic structure in which neither a hydroxyl group nor a cyanogroup is contained.

Ra represents a hydrogen atom, an alkyl group or a group of the formula—CH₂—O—Ra₂ in which Ra₂ represents a hydrogen atom, an alkyl group or anacyl group. Ra is preferably a hydrogen atom, a methyl group, ahydroxymethyl group or a trifluoromethyl group, further preferably ahydrogen atom or a methyl group.

The cyclic structures contained in R₅ include a monocyclic hydrocarbongroup and a polycyclic hydrocarbon group. As the monocyclic hydrocarbongroup, a cycloalkyl group having 3 to 12 carbon atoms and a cycloalkenylgroup having 3 to 12 carbon atoms can be exemplified. Preferably, themonocyclic hydrocarbon group is a monocyclic hydrocarbon group having 3to 7 carbon atoms.

The polycyclic hydrocarbon groups include ring-assembly hydrocarbongroups and crosslinked-ring hydrocarbon groups. As crosslinked-ringhydrocarbon rings, bicyclic hydrocarbon rings, tricyclic hydrocarbonrings, and tetracyclic hydrocarbon rings can be exemplified. Further,the crosslinked-ring hydrocarbon rings include condensed-ringhydrocarbon rings (for example, condensed rings resulting fromcondensation of multiple 5- to 8-membered cycloalkanes). As preferredcrosslinked-ring hydrocarbon rings, a norbornyl group and an adamantylgroup can be exemplified.

These alicyclic hydrocarbon groups may have substituents. As preferredsubstituents, a halogen atom, an alkyl group, a hydroxyl group protectedby a protective group, and an amino group protected by a protectivegroup can be exemplified. The halogen atom is preferably a bromine,chlorine or fluorine atom, and the alkyl group is preferably a methyl,ethyl, butyl or t-butyl group. The alkyl group may further have asubstituent. As the optional substituent, a halogen atom, an alkylgroup, a hydroxyl group protected by a protective group, and an aminogroup protected by a protective group can be exemplified.

As the protective group, an alkyl group, a cycloalkyl group, an aralkylgroup, a substituted methyl group, a substituted ethyl group, analkoxycarbonyl group and an aralkyloxycarbonyl group can be exemplified.Preferred alkyl groups include alkyl groups having 1 to 4 carbon atoms.Preferred substituted methyl groups include methoxymethyl,methoxythiomethyl, benzyloxymethyl, t-butoxymethyl and2-methoxyethoxymethyl groups. Preferred substituted ethyl groups include1-ethoxyethyl and 1-methyl-1-methoxyethyl groups. Preferred acyl groupsinclude aliphatic acyl groups having 1 to 6 carbon atoms, such asformyl, acetyl, propionyl, butyryl, isobutyryl, valeryl and pivaloylgroups. Preferred alkoxycarbonyl groups include alkoxycarbonyl groupshaving 1 to 4 carbon atoms and the like.

The content of repeating unit that has an alicyclic hydrocarbonstructure having no polar group and does not exhibit any aciddecomposability, based on all the repeating units of the resin (A), ispreferably in the range of 0 to 40 mol %, more preferably 0 to 20 mol %.

Specific examples of the repeating units that have an alicyclichydrocarbon structure having no polar group and do not exhibit any aciddecomposability will be shown, which however in no way limit the scopeof the present invention. In the formulae, Ra represents H, CH₃, CH₂OHor CF₃.

The resin for use in the actinic ray-sensitive or radiation-sensitiveresin composition of the present invention may have various repeatingstructural units other than the foregoing repeating structural units forthe purpose of regulating the dry etching resistance, standard developeradaptability, substrate adhesion, resist profile and generally requiredproperties of resists such as resolving power, heat resistance andsensitivity.

As such other repeating structural units, those corresponding to thefollowing monomers can be exemplified, which however are nonlimiting.

Such other repeating structural units would permit fine regulation ofthe properties required to have by the resin for use in the compositionof the present invention, especially, (1) solubility in appliedsolvents, (2) film forming easiness (glass transition temperature), (3)alkali developability, (4) film thinning (selection ofhydrophilicity/hydrophobicity and alkali-soluble group), (5) adhesion ofunexposed areas to substrate, (6) dry etching resistance, etc.

As the above-mentioned monomers, compounds having an unsaturated bondcapable of addition polymerization, selected from among acrylic esters,methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinylethers, vinyl esters and the like can be exemplified.

In addition, any unsaturated compound capable of addition polymerizationthat is copolymerizable with any of the monomers corresponding to theabove various repeating structural units may be copolymerized therewith.

The molar ratios of individual repeating structural units contained inthe resin (A) for use in the composition of the present invention areappropriately determined from the viewpoint of regulation of not onlythe resist dry etching resistance but also the standard developeradaptability, substrate adhesion, resist profile and generally requiredproperties of resists such as resolving power, heat resistance andsensitivity.

When the composition of the present invention is one for ArF exposure,it is preferred for the resin (A) for use in the composition of thepresent invention to have no aromatic group from the viewpoint oftransparency in ArF beams.

Further, it is preferred for the resin (A) not to contain a fluorineatom and a silicon atom from the viewpoint of compatibility with ahydrophobic resin (HR) to be described hereinbelow.

The resin (A) can be synthesized by conventional techniques (forexample, by radical polymerization). As general synthetic methods, abatch polymerization method in which a monomer species and an initiatorare dissolved in a solvent and heated so as to accomplishpolymerization, and a dropping polymerization method in which a solutionof monomer species and initiator is added by dropping to a heatedsolvent over a period of 1 to 10 hours can be exemplified and preferredis the dropping polymerization method. As a reaction solvent, an ether,such as tetrahydrofuran, 1,4-dioxane or diisopropyl ether; a ketone,such as methyl ethyl ketone or methyl isobutyl ketone; an ester solvent,such as ethyl acetate; an amide solvent, such as dimethylformamide ordimethylacetamide; and the later described solvent capable of dissolvingthe composition of the present invention, such as propylene glycolmonomethyl ether acetate, propylene glycol monomethyl ether orcyclohexanone can be exemplified. It is preferred to perform thepolymerization with the use of the same solvent as employed in theactinic ray-sensitive or radiation-sensitive resin composition accordingto the present invention. This would inhibit particle generation duringstorage.

The polymerization reaction is preferably carried out in an atmosphereof inert gas, such as nitrogen or argon. The polymerization is initiatedby the use of a commercially available radical initiator (azo initiator,peroxide, etc.) as a polymerization initiator. Among the radicalinitiators, an azo initiator is preferred. An azo initiator having anester group, a cyano group or a carboxy group is especially preferred.As preferred initiators, azobisisobutyronitrile,azobisdimethylvaleronitrile, and dimethyl2,2′-azobis(2-methylpropionate) can be exemplified. According tonecessity, a supplementation of initiator or divided addition thereofmay be effected. After the completion of the reaction, the reactionmixture is poured into a solvent. The desired polymer is recovered by amethod for powder or solid recovery, etc. The concentration during thereaction is in the range of 5 to 50 mass %, preferably 10 to 30 mass %.The reaction temperature is generally in the range of 10° C. to 150° C.,preferably 30° C. to 120° C., and more preferably 60° C. to 100° C.

The weight average molecular weight of the resin (A) in terms ofpolystyrene molecular weight as measured by GPC is preferably in therange of 1,000 to 200,000, more preferably 2,000 to 20,000, still morepreferably 3,000 to 15,000, and further preferably 3,000 to 10,000. Theregulation of the weight average molecular weight to 1,000 to 200,000would prevent deteriorations of heat resistance and dry etchingresistance and also prevent deterioration of developability and increaseof viscosity leading to poor film forming property.

Use is made of the resin whose degree of dispersal (molecular weightdistribution) is generally in the range of 1 to 3, preferably 1 to 2.6,more preferably 1 to 2, and most preferably 1.4 to 1.7. The lower themolecular weight distribution, the more excellent the resolving powerand resist profile and the smoother the side wall of the resist patternleading to an excellence in roughness.

The content of the resin (A) in the actinic ray-sensitive orradiation-sensitive resin composition according to the present inventionbased on the total solids thereof is preferably in the range of 50 to 99mass %, more preferably 60 to 95 mass %.

In the present invention, either solely one of the resins or acombination of two or more thereof may be used as the component (A).

[2] Compound (B) that generates an acid when exposed to actinic rays orradiation:

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention contains a compound that generates anacid when exposed to actinic rays or radiation (hereinafter alsoreferred to as “acid generator”).

As the acid generator, use can be made of a member appropriatelyselected from among a photoinitiator for photocationic polymerization, aphotoinitiator for photoradical polymerization, a photo-achromatic agentand photo-discoloring agent for dyes, any of publicly known compoundsthat generate an acid when exposed to actinic rays or radiation employedin microresists, etc., and mixtures thereof.

As the acid generator, a diazonium salt, a phosphonium salt, a sulfoniumsalt, an iodonium salt, an imide sulfonate, an oxime sulfonate,diazosulfone, disulfone and o-nitrobenzyl sulfonate can be exemplified.

Further, use can be made of compounds obtained by introducing any of theabove groups or compounds that generate an acid when exposed to actinicrays or radiation in a polymer principal chain or side chain, forexample, compounds described in U.S. Pat. No. 3,849,137, DE 3914407,JP-A's-63-26653, 55-164824, 62-69263, 63-146038, 63-163452, 62-153853,63-146029, etc.

Furthermore, use can be made of compounds that generate an acid whenexposed to light described in U.S. Pat. No. 3,779,778, EP 126,712, etc.

As preferred compounds among the acid generators, those represented bythe following general formulae ZI, ZII and ZIII can be exemplified.

In the above general formula ZI,

each of R₂₀₁, R₂₀₂ and R₂₀₃ independently represents an organic group.

The number of carbon atoms in the organic group represented by R₂₀₁,R₂₀₂ and R₂₀₃ is generally in the range of 1 to 30, preferably 1 to 20.

Two of R₂₀₁ to R₂₀₃ may be bonded to each other to form a ring, and thering within the same may contain an oxygen atom, a sulfur atom, an esterbond, an amido bond or a carbonyl group. As the group formed by bondingof two of R₂₀₁ to R₂₀₃, an alkylene group (for example, a butylene groupor a pentylene group) can be exemplified.

Z⁻ represents a nonnucleophilic anion.

As the nonnucleophilic anion represented by Z⁻, a sulfonate anion, acarboxylate anion, a sulfonylimido anion, a bis(alkylsulfonyl)imidoanion, and a tris(alkylsulfonyl)methyl anion can be exemplified.

The nonnucleophilic anion means an anion whose capability of inducing anucleophilic reaction is extremely low and is an anion capable ofinhibiting any temporal decomposition by intramolecular nucleophilicreaction. This would realize an enhancement of the temporal stability ofthe resist.

As the sulfonate anion, an aliphatic sulfonate anion, an aromaticsulfonate anion, and a camphor sulfonate anion can be exemplified.

As the carboxylate anion, an aliphatic carboxylate anion, an aromaticcarboxylate anion, and an aralkyl carboxylate anion can be exemplified.

The aliphatic moiety of the aliphatic sulfonate anion may be an alkylgroup or a cycloalkyl group, being preferably an alkyl group having 1 to30 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms. Assuch, a methyl group, an ethyl group, a propyl group, an isopropylgroup, an n-butyl group, an isobutyl group, a sec-butyl group, a pentylgroup, a neopentyl group, a hexyl group, a heptyl group, an octyl group,a nonyl group, a decyl group, an undecyl group, a dodecyl group, atridecyl group, a tetradecyl group, a pentadecyl group, a hexadecylgroup, a heptadecyl group, an octadecyl group, a nonadecyl group, aneicosyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexylgroup, an adamantyl group, a norbornyl group and a boronyl group can beexemplified.

As a preferred aromatic group of the aromatic sulfonate anion, an arylgroup having 6 to 14 carbon atoms, such as a phenyl group, a tolyl groupand a naphthyl group can be exemplified. The alkyl group, cycloalkylgroup and aryl group of the aliphatic sulfonate anion and aromaticsulfonate anion may have a substituent. As the substituent of the alkylgroup, cycloalkyl group and aryl group of the aliphatic sulfonate anionand aromatic sulfonate anion, a nitro group, a halogen atom (fluorineatom, chlorine atom, bromine atom or iodine atom), a carboxy group, ahydroxy group, an amino group, a cyano group, an alkoxy group(preferably having 1 to 15 carbon atoms), a cycloalkyl group (preferablyhaving 3 to 15 carbon atoms), an aryl group (preferably having 6 to 14carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbonatoms), an acyl group (preferably having 2 to 12 carbon atoms), analkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), analkylthio group (preferably having 1 to 15 carbon atoms), analkylsulfonyl group (preferably having 1 to 15 carbon atoms), analkyliminosulfonyl group (preferably having 2 to 15 carbon atoms), anaryloxysulfonyl group (preferably having 6 to 20 carbon atoms), analkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), acycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbonatoms), an alkyloxyalkyloxy group (preferably having 5 to 20 carbonatoms), and a cycloalkylalkyloxyalkyloxy group (preferably having 8 to20 carbon atoms) can be exemplified. The aryl group or ring structure ofthese groups may further have an alkyl group (preferably having 1 to 15carbon atoms) as its substituent.

As the aliphatic moiety of the aliphatic carboxylate anion, the samealkyl groups and cycloalkyl groups as mentioned with respect to thealiphatic sulfonate anion can be exemplified.

As the aromatic group of the aromatic carboxylate anion, the same arylgroups as mentioned with respect to the aromatic sulfonate anion can beexemplified.

As a preferred aralkyl group of the aralkyl carboxylate anion, anaralkyl group having 6 to 12 carbon atoms, such as a benzyl group, aphenethyl group, a naphthylmethyl group, a naphthylethyl group, and anaphthylbutyl group can be exemplified.

The alkyl group, cycloalkyl group, aryl group and aralkyl group of thealiphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. As the substituent of thealkyl group, cycloalkyl group, aryl group and aralkyl group of thealiphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion, the same halogen atom, alkyl group, cycloalkyl group,alkoxy group, and alkylthio group, etc. as mentioned with respect to thearomatic sulfonate anion can be exemplified.

As the sulfonylimido anion, a saccharin anion can be exemplified.

The alkyl group of the bis(alkylsulfonyl)imido anion andtris(alkylsulfonyl)methyl anion is preferably an alkyl group having 1 to5 carbon atoms. As such, a methyl group, an ethyl group, a propyl group,an isopropyl group, an n-butyl group, an isobutyl group, a sec-butylgroup, a pentyl group, and a neopentyl group can be exemplified. As asubstituent of these alkyl groups, a halogen atom, an alkyl groupsubstituted with a halogen atom, an alkoxy group, an alkylthio group, analkyloxysulfonyl group, an aryloxysulfonyl group, and acycloalkylaryloxysulfonyl group can be exemplified. An alkyl groupsubstituted with a fluorine atom is preferred.

As the other nonnucleophilic anions, phosphorus fluoride, boron fluorideand antimony fluoride can be exemplified.

The nonnucleophilic anion represented by Z⁻ is preferably selected fromamong an aliphatic sulfonate anion substituted at its α-position ofsulfonic acid with a fluorine atom, an aromatic sulfonate anionsubstituted with a fluorine atom or a group having a fluorine atom, abis(alkylsulfonyl)imido anion whose alkyl group is substituted with afluorine atom and a tris(alkylsulfonyl)methide anion whose alkyl groupis substituted with a fluorine atom. More preferably, thenonnucleophilic anion is a perfluorinated aliphatic sulfonate anionhaving 4 to 8 carbon atoms or a benzene sulfonate anion having afluorine atom. Still more preferably, the nonnucleophilic anion is anonafluorobutane sulfonate anion, a perfluorooctane sulfonate anion, apentafluorobenzene sulfonate anion or a 3,5-bis(trifluoromethyl)benzenesulfonate anion.

As the organic groups represented by R₂₀₁, R₂₀₂ and R₂₀₃, correspondinggroups in the following compounds (ZI-1), (ZI-2), (ZI-3) and (ZI-4) canbe exemplified.

Appropriate use may be made of compounds with two or more of thestructures of the general formula (ZI). For example, use may be made ofcompounds having a structure wherein at least one of R₂₀₁ to R₂₀₃ of acompound represented by the general formula (ZI) is bonded with at leastone of R₂₀₁ to R₂₀₃ of another compound represented by the generalformula (ZI).

As preferred (ZI) components, the following compounds (ZI-1), (ZI-2),(ZI-3) and (ZI-4) can be exemplified.

The compounds (ZI-1) are arylsulfonium compounds represented by thegeneral formula (ZI) wherein at least one of R₂₀₁ to R₂₀₃ is an arylgroup, namely, compounds containing an arylsulfonium as a cation.

In the arylsulfonium compounds, all of the R₂₀₁ to R₂₀₃ may be arylgroups. It is also appropriate that the R₂₀₁ to R₂₀₃ are partially anaryl group and the remainder is an alkyl group or a cycloalkyl group.

As the arylsulfonium compounds, a triarylsulfonium compound, adiarylalkylsulfonium compound, an aryldialkylsulfonium compound, adiarylcycloalkylsulfonium compound and an aryldicycloalkylsulfoniumcompound can be exemplified.

The aryl group of the arylsulfonium compounds is preferably a phenylgroup or a naphthyl group, more preferably a phenyl group. The arylgroup may be one having a heterocyclic structure containing an oxygenatom, nitrogen atom, sulfur atom or the like. As the aryl group having aheterocyclic structure, a pyrrole residue (group formed by loss of onehydrogen atom from pyrrole), a furan residue (group formed by loss ofone hydrogen atom from furan), a thiophene residue (group formed by lossof one hydrogen atom from thiophene), an indole residue (group formed byloss of one hydrogen atom from indole), a benzofuran residue (groupformed by loss of one hydrogen atom from benzofuran), and abenzothiophene residue (group formed by loss of one hydrogen atom frombenzothiophene) can be exemplified. When the arylsulfonium compound hastwo or more aryl groups, the two or more aryl groups may be identical toor different from each other.

The alkyl group or cycloalkyl group contained in the arylsulfoniumcompound according to necessity is preferably a linear or branched alkylgroup having 1 to 15 carbon atoms or a cycloalkyl group having 3 to 15carbon atoms. As such, a methyl group, an ethyl group, a propyl group,an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropylgroup, a cyclobutyl group, and a cyclohexyl group can be exemplified.

The aryl group, alkyl group or cycloalkyl group represented by R₂₀₁ toR₂₀₃ may have as its substituent an alkyl group (having, for example, 1to 15 carbon atoms), a cycloalkyl group (having, for example, 3 to 15carbon atoms), an aryl group (having, for example, 6 to 14 carbonatoms), an alkoxy group (having, for example, 1 to 15 carbon atoms), ahalogen atom, a hydroxy group or a phenylthio group. Preferredsubstituents include a linear or branched alkyl group having 1 to 12carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and alinear, branched or cyclic alkoxy group having 1 to 12 carbon atoms.More preferred substituents include an alkyl group having 1 to 4 carbonatoms and an alkoxy group having 1 to 4 carbon atoms. The substituentsmay be contained in any one of the three R₂₀₁ to R₂₀₃, or alternativelymay be contained in all three of R₂₀₁ to R₂₀₃. When R₂₀₁ to R₂₀₃represent an aryl group, the substituent preferably lies at thep-position of the aryl group.

Now, the compounds (ZI-2) will be described.

The compounds (ZI-2) are compounds represented by the formula (ZI)wherein each of R₂₀₁ to R₂₀₃ independently represents an organic grouphaving no aromatic ring. The aromatic rings include an aromatic ringhaving a heteroatom.

The organic group having no aromatic ring represented by R₂₀₁ to R₂₀₃generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

Preferably, each of R₂₀₁ to R₂₀₃ independently represents an alkylgroup, a cycloalkyl group, an allyl group or a vinyl group. Morepreferred groups include a linear or branched 2-oxoalkyl group, a2-oxocycloalkyl group and an alkoxycarbonylmethyl group. Especiallypreferred is a linear or branched 2-oxoalkyl group.

As preferred alkyl groups and cycloalkyl groups represented by R₂₀₁ toR₂₀₃, a linear or branched alkyl group having 1 to 10 carbon atoms (forexample, a methyl group, an ethyl group, a propyl group, a butyl groupor a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms(for example, a cyclopentyl group, a cyclohexyl group or a norbornylgroup) can be exemplified. As more preferred alkyl groups, a 2-oxoalkylgroup and an alkoxycarbonylmethyl group can be exemplified. As morepreferred cycloalkyl group, a 2-oxocycloalkyl group can be exemplified.

The 2-oxoalkyl group may be linear or branched. A group having >C═O atthe 2-position of the alkyl group can be preferably exemplified.

The 2-oxocycloalkyl group is preferably a group having >C═O at the2-position of the cycloalkyl group.

As preferred alkoxy groups of the alkoxycarbonylmethyl group, alkoxygroups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, apropoxy group, a butoxy group and a pentoxy group) can be exemplified.

The R₂₀₁ to R₂₀₃ may be further substituted with a halogen atom, analkoxy group (having, for example, 1 to 5 carbon atoms), a hydroxygroup, a cyano group or a nitro group.

The compounds (ZI-3) are those represented by the following generalformula (ZI-3) which have a phenacylsulfonium salt structure.

In the general formula (ZI-3),

each of R_(1c) to R_(5c) independently represents a hydrogen atom, analkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.

Each of R_(6c) and R_(7c) independently represents a hydrogen atom, analkyl group or a cycloalkyl group.

Each of R_(x) and R_(y) independently represents an alkyl group, acycloalkyl group, an allyl group or a vinyl group.

Any two or more of R_(1c) to R_(5c); R_(6c) and R_(7c); and R_(x) andR_(y) may be bonded to each other to form a ring. This ring may containan oxygen atom, a sulfur atom, an ester bond or an amido bond. As thegroup formed by bonding of any two or more of R_(1c) to R_(5c); R_(6c)and R_(7c); and R_(x) and R_(y), a butylene group and a pentylene groupcan be exemplified.

Z_(c) ⁻ represents a nonnucleophilic anion. The same nonnucleophilicanions as mentioned with respect to the Z⁻ in the general formula (ZI)can be exemplified.

The alkyl group represented by R_(1c) to R_(7c) may be linear orbranched. As such, an alkyl group having 1 to 20 carbon atoms,preferably a linear or branched alkyl group having 1 to 12 carbon atoms(for example, a methyl group, an ethyl group, a linear or branchedpropyl group, a linear or branched butyl group or a linear or branchedpentyl group) can be exemplified. As the cycloalkyl group, a cycloalkylgroup having 3 to 8 carbon atoms (for example, a cyclopentyl group or acyclohexyl group) can be exemplified.

The alkoxy group represented by R_(1c) to R_(5c) may be linear,branched, or cyclic. As such, an alkoxy group having 1 to 10 carbonatoms, preferably a linear or branched alkoxy group having 1 to 5 carbonatoms (for example, a methoxy group, an ethoxy group, a linear orbranched propoxy group, a linear or branched butoxy group or a linear orbranched pentoxy group) and a cycloalkoxy group having 3 to 8 carbonatoms (for example, a cyclopentyloxy group or a cyclohexyloxy group) canbe exemplified.

Preferably, any one of R_(1c) to R_(5c) is a linear or branched alkylgroup, a cycloalkyl group or a linear, branched or cyclic alkoxy group.More preferably, the sum of the number of carbon atoms in R_(1c) toR_(5c) is in the range of 2 to 15. Accordingly, there can be attained anenhancement of solvent solubility and inhibition of particle generationduring storage.

As the alkyl groups and cycloalkyl groups represented by R_(x) andR_(y), the same alkyl groups and cycloalkyl groups as mentioned withrespect to R_(1c) to R_(7c) can be exemplified. Among them, a 2-oxoalkylgroup, a 2-oxocycloalkyl group and an alkoxycarbonylmethyl group aremore preferred.

As the 2-oxoalkyl group and 2-oxocycloalkyl group, groups having >C═O atthe 2-position of the alkyl group and cycloalkyl group represented byR_(1c) to R_(7c) can be exemplified.

Regarding the alkoxy group of the alkoxycarbonylmethyl group, the samealkoxy groups as mentioned with respect to R_(1c) to R_(5c) can beexemplified.

Each of R_(x) and R_(y) is preferably an alkyl group or cycloalkyl grouphaving 4 or more carbon atoms. The alkyl group or cycloalkyl group hasmore preferably 6 or more carbon atoms, and still more preferably 8 ormore carbon atoms.

The compounds (ZI-4) are those represented by general formula (ZI-4)below.

In the general formula (ZI-4),

R₁₃ represents a hydrogen atom, a fluorine atom, a hydroxyl group, analkyl group, a cycloalkyl group, an alkoxy group or an alkoxycarbonylgroup.

R₁₄, each independently in the presence of two or more groups,represents an alkyl group, a cycloalkyl group, an alkoxy group, analkylsulfonyl group or a cycloalkylsulfonyl group.

Each of R₁₅s independently represents an alkyl group or a cycloalkylgroup, provided that the two R₁₅s may be bonded to each other to therebyform a ring.

In the formula, l is an integer of 0 to 2, and

r is an integer of 0 to 10.

Z⁻ represents a nonnucleophilic anion. As such, any of the samenonnucleophilic anions as mentioned with respect to the Z⁻ of thegeneral formula (ZI) can be exemplified.

In the general formula (ZI-4), the alkyl groups represented by R₁₃, R₁₄and R₁₅ may be linear or branched and preferably each have 1 to 10carbon atoms. As such, a methyl group, an ethyl group, an n-propylgroup, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a1-methylpropyl group, a t-butyl group, an n-pentyl group, a neopentylgroup, an n-hexyl group, an n-heptyl group, an n-octyl group, a2-ethylhexyl group, an n-nonyl group, and an n-decyl group can beexemplified. Preferred alkyl groups include a methyl group, an ethylgroup, an n-butyl group, and a t-butyl group.

As the cycloalkyl groups represented by R₁₃, R₁₄ and R₁₅, a cyclopropyl,a cyclobutyl, a cyclopentyl, a cyclohexyl, a cycloheptyl, a cyclooctyl,a cyclododecanyl, a cyclopentenyl, a cyclohexenyl, and a cyclooctadienylgroup can be exemplified. Cyclopropyl, cyclopentyl, cyclohexyl andcyclooctyl groups are especially preferred.

The alkoxy groups represented by R₁₃ and R₁₄ may be linear or branchedand preferably each have 1 to 10 carbon atoms. As such, a methoxy group,an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxygroup, a 2-methylpropoxy group, a 1-methylpropoxy group, a t-butoxygroup, an n-pentyloxy group, a neopentyloxy group, an n-hexyloxy group,an n-heptyloxy group, an n-octyloxy group, a 2-ethylhexyloxy group, ann-nonyloxy group, and an n-decyloxy group can be exemplified. Preferredalkoxy groups include a methoxy group, an ethoxy group, an n-propoxygroup, and an n-butoxy group.

The alkoxycarbonyl group represented by R₁₃ may be linear or branchedand preferably has 2 to 11 carbon atoms. As such, a methoxycarbonylgroup, an ethoxycarbonyl group, an n-propoxycarbonyl group, ani-propoxycarbonyl group, an n-butoxycarbonyl group, a2-methylpropoxycarbonyl group, a 1-methylpropoxycarbonyl group, at-butoxycarbonyl group, an n-pentyloxycarbonyl group, aneopentyloxycarbonyl group, an n-hexyloxycarbonyl group, ann-heptyloxycarbonyl group, an n-octyloxycarbonyl group, a2-ethylhexyloxycarbonyl group, an n-nonyloxycarbonyl group, and ann-decyloxycarbonyl group can be exemplified. Preferred alkoxycarbonylgroups include a methoxycarbonyl group, an ethoxycarbonyl group, and ann-butoxycarbonyl group.

The alkylsulfonyl and cycloalkylsulfonyl groups represented by R₁₄ maybe linear, branched or cyclic and preferably each have 1 to 10 carbonatoms. As such, a methanesulfonyl group, an ethanesulfonyl group, ann-propanesulfonyl group, an n-butanesulfonyl group, atert-butanesulfonyl group, an n-pentanesulfonyl group, aneopentanesulfonyl group, an n-hexanesulfonyl group, ann-heptanesulfonyl group, an n-octanesulfonyl group, a2-ethylhexanesulfonyl group, an n-nonanesulfonyl group, ann-decanesulfonyl group, a cyclopentanesulfonyl group, and acyclohexanesulfonyl group can be exemplified. Preferred alkylsulfonyland cycloalkylsulfonyl groups include a methanesulfonyl group, anethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonylgroup, a cyclopentanesulfonyl group, and a cyclohexanesulfonyl group.

In the formula, l is preferably 0 or 1, more preferably 1, and r ispreferably 0 to 2.

Each of the R₁₃, R₁₄ and R₁₅ groups may have a substituent. As such asubstituent, a halogen atom (e.g., a fluorine atom), a hydroxyl group, acarboxyl group, a cyano group, a nitro group, an alkoxy group, analkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxygroup can be exemplified.

As the alkoxy group, a linear, branched or cyclic alkoxy group having 1to 20 carbon atoms, such as a methoxy group, an ethoxy group, ann-propoxy group, an i-propoxy group, an n-butoxy group, a2-methylpropoxy group, a 1-methylpropoxy group, a t-butoxy group, acyclopentyloxy group and a cyclohexyloxy group can be exemplified.

As the alkoxyalkyl group, a linear, branched or cyclic alkoxyalkyl grouphaving 2 to 21 carbon atoms, such as a methoxymethyl group, anethoxymethyl group, a 1-methoxyethyl group, a 2-methoxyethyl group, a1-ethoxyethyl group and a 2-ethoxyethyl group can be exemplified.

As the alkoxycarbonyl group, a linear, branched or cyclic alkoxycarbonylgroup having 2 to 21 carbon atoms, such as a methoxycarbonyl group, anethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonylgroup, an n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, a1-methylpropoxycarbonyl group, a t-butoxycarbonyl group, acyclopentyloxycarbonyl group and a cyclohexyloxycarbonyl group can beexemplified.

As the alkoxycarbonyloxy group, a linear, branched or cyclicalkoxycarbonyloxy group having 2 to 21 carbon atoms, such as amethoxycarbonyloxy group, an ethoxycarbonyloxy group, ann-propoxycarbonyloxy group, an i-propoxycarbonyloxy group, ann-butoxycarbonyloxy group, a t-butoxycarbonyloxy group, acyclopentyloxycarbonyloxy group and a cyclohexyloxycarbonyloxy group canbe exemplified.

The cyclic structure that may be formed by the bonding of the two R₁₅sto each other is preferably a 5- or 6-membered ring, especially a5-membered ring (namely, a tetrahydrothiophene ring) formed by twobivalent R₁₅s in cooperation with the sulfur atom of the general formula(ZI-4). The bivalent R₁₅s may have substituents. As such substituents, ahydroxyl group, a carboxyl group, a cyano group, a nitro group, analkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group, and analkoxycarbonyloxy group as mentioned above can be exemplified. It isespecially preferred for the R₁₅ of the general formula (ZI-4) to be amethyl group, an ethyl group, the above-mentioned bivalent groupallowing two R₁₅s to be bonded to each other so as to form atetrahydrothiophene ring structure in cooperation with the sulfur atomof the general formula (ZI-4), or the like.

As mentioned above, the alkyl group, cycloalkyl group, alkoxy group andalkoxycarbonyl group represented by R₁₃ as well as the alkyl group,cycloalkyl group, alkoxy group, alkylsulfonyl group andcycloalkylsulfonyl group represented by R₁₄ may have substituents.Preferred substituents are a hydroxyl group, an alkoxy group, analkoxycarbonyl group and a halogen atom (especially, a fluorine atom).

Preferred specific examples of the cations of the compounds of thegeneral formula (ZI-4) will be shown below.

Specific examples of the cations contained in compounds represented bythe general formula (ZI) will further be shown below.

In the general formulae (ZII) and (ZIII),

each of R₂₀₄ to R₂₀₇ independently represents an aryl group, an alkylgroup or a cycloalkyl group.

The aryl group represented by R₂₀₄ to R₂₀₇ is preferably a phenyl groupor a naphthyl group, more preferably a phenyl group. The aryl grouprepresented by R₂₀₄ to R₂₀₇ may be one having a heterocyclic structurecontaining an oxygen atom, nitrogen atom, sulfur atom, etc. As the arylgroup having a heterocyclic structure, a pyrrole residue (group formedby loss of one hydrogen atom from pyrrole), a furan residue (groupformed by loss of one hydrogen atom from furan), a thiophene residue(group formed by loss of one hydrogen atom from thiophene), an indoleresidue (group formed by loss of one hydrogen atom from indole), abenzofuran residue (group formed by loss of one hydrogen atom frombenzofuran), and a benzothiophene residue (group formed by loss of onehydrogen atom from benzothiophene) can be exemplified.

As preferred alkyl groups and cycloalkyl groups represented by R₂₀₄ toR₂₀₇, a linear or branched alkyl group having 1 to 10 carbon atoms (forexample, a methyl group, an ethyl group, a propyl group, a butyl groupor a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms(for example, a cyclopentyl group, a cyclohexyl group or a norbornylgroup) can be exemplified.

The aryl group, alkyl group and cycloalkyl group represented by R₂₀₄ toR₂₀₇ may have a substituent. As a possible substituent on the arylgroup, alkyl group and cycloalkyl group represented by R₂₀₄ to R₂₀₇, analkyl group (having, for example, 1 to 15 carbon atoms), a cycloalkylgroup (having, for example, 3 to 15 carbon atoms), an aryl group(having, for example, 6 to 15 carbon atoms), an alkoxy group (having,for example, 1 to 15 carbon atoms), a halogen atom, a hydroxy group, anda phenylthio group can be exemplified.

Z⁻ represents a nonnucleophilic anion. As such, the same nonnucleophilicanions as mentioned with respect to the Z⁻ in the general formula (ZI)can be exemplified.

Specific examples of the cations contained in compounds represented bythe general formula (ZII) will be shown below.

As the acid generators, the compounds represented by the followinggeneral formulae (ZIV), (ZV) and (ZVI) can further be exemplified.

In the general formulae (ZIV) to (ZVI),

each of Ar₃ and Ar₄ independently represents an aryl group.

Each of R₂₀₈, R₂₀₉ and R₂₁₀ independently represents an alkyl group, acycloalkyl group or an aryl group.

A represents an alkylene group, an alkenylene group or an arylene group.

Among the acid generators, the compounds represented by the generalformulae (ZI) to (ZIII) are more preferred.

As a preferred acid generator, a compound that generates an acid havingone sulfonate group or imido group. As a more preferred acid generator,a compound that generates a monovalent perfluoroalkanesulfonic acid, acompound that generates a monovalent aromatic sulfonic acid substitutedwith a fluorine atom or fluorine-atom-containing group, and a compoundthat generates a monovalent imidic acid substituted with a fluorine atomor fluorine-atom-containing group can be exemplified. As a still morepreferred acid generator, any of sulfonium salts of fluorinatedalkanesulfonic acid, fluorinated benzenesulfonic acid, fluorinatedimidic acid and fluorinated methide acid can be exemplified. Withrespect to practicable acid generators, it is especially preferred forthe generated acid to be a fluorinated alkanesulfonic acid, fluorinatedbenzenesulfonic acid or fluorinated imidic acid, each of which havingpKa's of −1 or below. By the use thereof, an enhancement of sensitivitycan be attained.

Furthermore, as the acid generator, compounds that generate any of theacids of general formula (IV) below when exposed to actinic rays orradiation can be exemplified.

In the formula,

each of Xfs independently represents a fluorine atom or an alkyl groupsubstituted with at least one fluorine atom.

Each of R¹ and R² independently represents a member selected from amonga hydrogen atom, a fluorine atom, an alkyl group and an alkyl groupsubstituted with at least one fluorine atom. When two or more R¹s or R²sare contained, the two or more may be identical to or different fromeach other.

L represents a single bond or a bivalent connecting group. When two ormore Ls are contained, they may be identical to or different from eachother.

A represents a group with a cyclic structure.

In the formula, x is an integer of 1 to 20, y an integer of 0 to 10 andz an integer of 0 to 10.

The general formula (IV) will be described in detail below.

The alkyl group of the alkyl group substituted with at least onefluorine atom, represented by Xf has preferably 1 to 10 carbon atoms,more preferably 1 to 4 carbon atoms. The alkyl group substituted with atleast one fluorine atom, represented by Xf is preferably aperfluoroalkyl group.

Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4carbon atoms. In particular, a fluorine atom, CF₃, C₂F₅, C₃F₇, C₄F₉,C₅F₁₁, C₆F₁₃, C₇F₁₅, C₈F₁₇, CH₂CF₃, CH₂CH₂CF₃, CH₂C₂F₅, CH₂CH₂C₂F₅,CH₂C₃F₇, CH₂CH₂C₃F₇, CH₂C₄F₉ and CH₂CH₂C₄F₉ can be exemplified. Ofthese, a fluorine atom and CF₃ are preferred. Further preferably, bothof the Xfs are fluorine atoms.

Each of the alkyl group and the alkyl group of the alkyl groupsubstituted with at least one fluorine atom, represented by each of R¹and R² has preferably 1 to 4 carbon atoms. Further preferably, each ofthe alkyl groups is a perfluoroalkyl group having 1 to 4 carbon atoms.In particular, CF₃, C₂F₅, C₃F₇, C₄F₉, C₅F₁₁, C₆F₁₃, C₇F₁₅, C₈F₁₇,CH₂CF₃, CH₂CH₂CF₃, CH₂C₂F₅, CH₂CH₂C₂F₅, CH₂C₃F₇, CH₂CH₂C₃F₇, CH₂C₄F₉ andCH₂CH₂C₄F₉ can be exemplified. Of these, CF₃ is preferred.

In the formula, y is preferably 0 to 4, more preferably 0; x ispreferably 1 to 8, more preferably 1 to 4 and most preferably 1; and zis preferably 0 to 8, more preferably 0 to 4.

The bivalent connecting group represented by L is not particularlylimited. As the same, —COO—, —OCO—, —CO—, —O—, —S—, —SO—, —SO₂—, analkylene group, a cycloalkylene group, and an alkenylene group can beexemplified. Of these, —COO—, —OCO—, —CO— and —O— are preferred. —COO—and —OCO— are more preferred.

The group with a cyclic structure represented by A is not particularlylimited as long as a cyclic structure is contained. As the group, analicyclic group, an aryl group, and a group with any of heterocyclicstructures (including not only those exhibiting aromaticity but alsothose exhibiting no aromaticity) can be exemplified.

The alicyclic group may be monocyclic or polycyclic. Preferably, thealicyclic group is a cycloalkyl group of a single ring, such as acyclopentyl group, a cyclohexyl group or a cyclooctyl group, or acycloalkyl group of multiple rings, such as a norbornyl group, atricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanylgroup or an adamantyl group. Of the mentioned groups, alicyclic groupswith a bulky structure having at least 7 carbon atoms, namely, anorbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, atetracyclododecanyl group and an adamantyl group are preferred from theviewpoint of inhibition of in-film diffusion in the PEB (post-exposurebake) stage that would enhance MEEF.

As the aryl group, a benzene ring, a naphthalene ring, a phenanthrenering and an anthracene ring can be exemplified. Of these, naphthalene oflow absorbance is preferred from the viewpoint of absorbance at 193 nm.

As the group with a heterocyclic structure, a furan ring, a thiophenering, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, adibenzothiophene ring and a pyridine ring can be exemplified. Of these,a furan ring, a thiophene ring and a pyridine ring are preferred.

The above group with a cyclic structure may have a substituent. As thesubstituent, an alkyl group (may be linear, branched or cyclic,preferably having 1 to 12 carbon atoms), an aryl group (preferablyhaving 6 to 14 carbon atoms), a hydroxyl group, an alkoxy group, anester group, an amido group, a urethane group, a ureido group, athioether group, a sulfonamido group, and a sulfonic ester group can beexemplified.

The general formulae (IVa) and (IVb) below are preferred forms of thegeneral formula (IV) above. In the general formulae (IVa) and (IVb), Xf,R¹, R², L, A, y and z are as defined in the general formula (IV) above.

As preferred compounds capable of generating any of the acidsrepresented by the general formula (IV) upon exposure to actinic rays orradiation, a compound with an ionic structure, such as a sulfonium saltor an iodonium salt, and a compound with a nonionic structure, such asan oxime ester or an imide ester can be exemplified. As the compoundwith an ionic structure, any of those represented by the generalformulae (ZI) and (ZII) above can be exemplified. In the generalformulae (ZI) and (ZII), Z⁻ represents the anion structure of the acidsof the general formula (IV).

Further, as compounds capable of generating any of the acids of thegeneral formula (IV) upon exposure to actinic rays or radiation, thecompounds represented by general formulae (ZV′) and (ZVI′) below can beexemplified.

In the general formulas (ZV′) and (ZVI′),

each of R₂₀₉ and R₂₁₀ independently represents an alkyl group, acycloalkyl group or an aryl group.

A represents an alkylene group, an alkenylene group or an arylene group.

Rz represents a structure resulting from dissociation of H from any ofthe acids of the general formula (IV) and is expressed by the generalformula (I-s) below.

In the formula, R₁, R₂, L, A, Xf, x, y and z are as defined in thegeneral formula (IV) above, and * represents the site of bonding withany of the residues of the compounds of the general formulae (ZV′) and(ZVI′).

Specific examples of the residues of the compounds represented by thegeneral formulae (ZV′) and (ZVI′) will be shown below.

Specific examples of acids represented by general formula (I) will beshown below.

Of the specific examples above, particularly preferred acids will beshown below.

Particularly preferred examples of the acid generators are as follows.

As compounds (B) especially preferred for enhancing the effects of thepresent invention, those represented by general formula (I) below can beexemplified.

In the general formula (I),

X⁺ represents an organic counter ion, and R represents a hydrogen atomor a substituent having 1 or more carbon atoms.

R is preferably an organic group having 1 to 40 carbon atoms, morepreferably an organic group having 3 to 40 carbon atoms, and mostpreferably any of the organic groups represented by the followingformula (II).

—(CH₂)_(n)—Rc-(Y)_(m)  (II)

In the formula (II),

Rc represents a monocyclic or polycyclic organic group having 3 to 30carbon atoms that may contain a cyclic ether, cyclic thioether, cyclicketone, cyclic carbonate ester, lactone or lactam structure.

Y represents a hydroxy group, a halogen atom, a cyano group, a carboxygroup, a hydrocarbon group having 1 to 10 carbon atoms, a hydroxyalkylgroup having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbonatoms, an acyl group having 1 to 10 carbon atoms, an alkoxycarbonylgroup having 2 to 10 carbon atoms, an acyloxy group having 2 to 10carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms or ahalogenated alkyl group having 1 to 8 carbon atoms.

In the formula, m is an integer of 0 to 6. In the event of multiple Ys,they may be identical to or different from each other.

Further, n is an integer of 0 to 10. The number of carbon atomsconstructing each of the groups R expressed by the formula (II) is 40 orless.

As preferred forms of the compounds of the general formula (I), those ofthe general formulae (Z_(SC1)) and (Z_(IC1)) can be exemplified.

In the general formula (Z_(SC1)),

the definition of R and preferred scope thereof are the same as in thegeneral formula (I).

Each of R₂₀₁, R₂₀₂ and R₂₀₃ independently represents an organic group.

The number of carbon atoms in each of the organic groups represented byR₂₀₁, R₂₀₂ and R₂₀₃ is generally in the range of 1 to 30, preferably 1to 20.

Two of R₂₀₁ to R₂₀₃ may be bonded to each other to form a ring, and thering within the same may contain an oxygen atom, a sulfur atom, an esterbond, an amido bond or a carbonyl group. As the group formed by bondingof two of R₂₀₁ to R₂₀₃, an alkylene group (for example, a butylene groupor a pentylene group) can be exemplified.

As organic groups represented by R₂₀₁, R₂₀₂ and R₂₀₃, correspondinggroups in the following compounds (Z_(SC1)-1), (Z_(SC1)-2) and(Z_(SC1)-3) can be exemplified.

Appropriate use may be made of compounds with two or more of thestructures represented by the general formula (Z_(SC1)). For example,use may be made of compounds having a structure wherein at least one ofR₂₀₁ to R₂₀₃ of a compound represented by the general formula Z_(SC1) isbonded to at least one of R₂₀₁ to R₂₀₃ of another compound representedby the general formula (Z_(SC1)).

As preferred (Z_(SC1)) components, the following compounds (Z_(SC1)-1),(Z_(SC1)-2) and (Z_(SC1)-3) can be exemplified.

The compounds (Z_(SC1)-1) are arylsulfonium compounds of the generalformula (Z_(SC1)) wherein at least one of R₂₀₁ to R₂₀₃ is an aryl group,namely, compounds containing an arylsulfonium as a cation. Thedefinition of R and preferred scope thereof are the same as in thegeneral formula (I).

In the arylsulfonium compounds, all of the R₂₀₁ to R₂₀₃ may be arylgroups. It is also appropriate if the R₂₀₁ to R₂₀₃ are partially an arylgroup and the remainder is an alkyl group or a cycloalkyl group.

As the arylsulfonium compounds, a triarylsulfonium compound, adiarylalkylsulfonium compound, an aryldialkylsulfonium compound, adiarylcycloalkylsulfonium compound and an aryldicycloalkylsulfoniumcompound can be exemplified.

The aryl group of the arylsulfonium compounds is preferably a phenylgroup or a naphthyl group, more preferably a phenyl group. The arylgroup may be one having a heterocyclic structure containing an oxygenatom, a nitrogen atom, a sulfur atom, etc. As the aryl group having aheterocyclic structure, a pyrrole residue (group formed by loss of onehydrogen atom from pyrrole), a furan residue (group formed by loss ofone hydrogen atom from furan), a thiophene residue (group formed by lossof one hydrogen atom from thiophene), an indole residue (group formed byloss of one hydrogen atom from indole), a benzofuran residue (groupformed by loss of one hydrogen atom from benzofuran), and abenzothiophene residue (group formed by loss of one hydrogen atom frombenzothiophene) can be exemplified. When the arylsulfonium compound hastwo or more aryl groups, the two or more aryl groups may be identical toor different from each other.

The alkyl group or cycloalkyl group contained in the arylsulfoniumcompound according to necessity is preferably a linear or branched alkylgroup having 1 to 15 carbon atoms or a cycloalkyl group having 3 to 15carbon atoms. As such, a methyl group, an ethyl group, a propyl group,an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropylgroup, a cyclobutyl group, and a cyclohexyl group can be exemplified.

The aryl group, alkyl group or cycloalkyl group represented by R₂₀₁ toR₂₀₃ may have as its substituent an alkyl group (having, for example, 1to 15 carbon atoms), a cycloalkyl group (having, for example, 3 to 15carbon atoms), an aryl group (having, for example, 6 to 14 carbonatoms), an alkoxy group (having, for example, 1 to 15 carbon atoms), ahalogen atom, a hydroxy group or a phenylthio group. Preferredsubstituents include a linear or branched alkyl group having 1 to 12carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, and alinear, branched or cyclic alkoxy group having 1 to 12 carbon atoms.More preferred substituents include an alkyl group having 1 to 4 carbonatoms and an alkoxy group having 1 to 4 carbon atoms. The substituentsmay be contained in any one of the three R₂₀₁ to R₂₀₃, or alternativelymay be contained in all three of R₂₀₁ to R₂₀₃. When R₂₀₁ to R₂₀₃represent an aryl group, the substituent preferably lies at thep-position of the aryl group.

Now, the compounds (Z_(SC1)-2) will be described.

The compounds (Z_(SC1)-2) are compounds of the formula (Z_(SC1)) whereineach of R₂₀₁ to R₂₀₃ independently represents an organic group having noaromatic ring. The aromatic rings include an aromatic ring having aheteroatom. The definition of R and preferred scope thereof are the sameas in the general formula (I).

The organic group having no aromatic ring represented by R₂₀₁ to R₂₀₃generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

Preferably, each of R₂₀₁ to R₂₀₃ independently represents an alkylgroup, a cycloalkyl group, an allyl group or a vinyl group. Morepreferred groups include a linear or branched 2-oxoalkyl group, a2-oxocycloalkyl group and an alkoxycarbonylmethyl group. Especiallypreferred is a linear or branched 2-oxoalkyl group.

As preferred alkyl groups and cycloalkyl groups represented by R₂₀₁ toR₂₀₃, a linear or branched alkyl group having 1 to 10 carbon atoms (forexample, a methyl group, an ethyl group, a propyl group, a butyl groupor a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms(for example, a cyclopentyl group, a cyclohexyl group or a norbornylgroup) can be exemplified. As more preferred alkyl groups, a 2-oxoalkylgroup and an alkoxycarbonylmethyl group can be exemplified. As a morepreferred cycloalkyl group, a 2-oxocycloalkyl group can be exemplified.

The 2-oxoalkyl group may be linear or branched. A group having >C═O atthe 2-position of the alkyl group is preferred.

The 2-oxocycloalkyl group is preferably a group having >C═O at the2-position of the cycloalkyl group.

As preferred alkoxy groups of the alkoxycarbonylmethyl group, alkoxygroups having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, apropoxy group, a butoxy group and a pentoxy group) can be exemplified.

The R₂₀₁ to R₂₀₃ may be further substituted with a halogen atom, analkoxy group (having, for example, 1 to 5 carbon atoms), a hydroxygroup, a cyano group or a nitro group.

The compounds (Z_(SC1)-3) are those represented by the following generalformula (Z_(SC1)-3), which have a phenacylsulfonium salt structure.

In the general formula (Z_(SC1)-3),

the definition of R and preferred scope thereof are the same as in thegeneral formula (I).

Each of R_(1c) to R_(5c) independently represents a hydrogen atom, analkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.

Each of R_(6c) and R_(7c) independently represents a hydrogen atom, analkyl group or a cycloalkyl group.

Each of R_(x) and R_(y) independently represents an alkyl group, acycloalkyl group, an allyl group or a vinyl group.

Any two or more of R_(1c) to R_(5c); R_(6c) and R_(7c); and R_(x) andR_(y) may be bonded to each other to form a ring. This ring may containan oxygen atom, a sulfur atom, an ester bond or an amido bond. As thegroup formed by bonding of any two or more of R_(1c) to R_(5c); R_(6c)and R_(7c); and R_(x) and R_(y), a butylene group and a pentylene groupcan be exemplified.

The alkyl group represented by R_(1c) to R_(7c) may be linear orbranched. As such, an alkyl group having 1 to 20 carbon atoms,preferably a linear or branched alkyl group having 1 to 12 carbon atoms(for example, a methyl group, an ethyl group, a linear or branchedpropyl group, a linear or branched butyl group or a linear or branchedpentyl group) can be exemplified. As the cycloalkyl group, a cycloalkylgroup having 3 to 8 carbon atoms (for example, a cyclopentyl group or acyclohexyl group) can be exemplified.

The alkoxy group represented by R_(1c) to R_(5c) may be linear,branched, or cyclic. As such, an alkoxy group having 1 to 10 carbonatoms, preferably a linear or branched alkoxy group having 1 to 5 carbonatoms (for example, a methoxy group, an ethoxy group, a linear orbranched propoxy group, a linear or branched butoxy group or a linear orbranched pentoxy group) and a cycloalkoxy group having 3 to 8 carbonatoms (for example, a cyclopentyloxy group or a cyclohexyloxy group) canbe exemplified.

Preferably, any one of R_(1c) to R_(5c) is a linear or branched alkylgroup, a cycloalkyl group, or a linear, branched or cyclic alkoxy group.More preferably, the sum of the number of carbon atoms in R_(1c) toR_(5c) is in the range of 2 to 15. Accordingly, there can be attained anenhancement of solvent solubility and inhibition of particle generationduring storage.

As the alkyl groups and cycloalkyl groups represented by R_(x) andR_(y), the same alkyl groups and cycloalkyl groups as mentioned withrespect to R_(1c) to R_(7c) can be exemplified. Among them, a 2-oxoalkylgroup, a 2-oxocycloalkyl group and an alkoxycarbonylmethyl group arepreferred.

As the 2-oxoalkyl group and 2-oxocycloalkyl group, groups having >C═O atthe 2-position of the alkyl group and cycloalkyl group represented byR_(1c) to R_(7c) can be exemplified.

Regarding the alkoxy group of the alkoxycarbonylmethyl group, the samealkoxy groups as mentioned with respect to R_(1c) to R_(5c) can beexemplified.

Each of R_(x) and R_(y) is preferably an alkyl group or cycloalkyl grouphaving 4 or more carbon atoms. The alkyl group or cycloalkyl group hasmore preferably 6 or more carbon atoms and still more preferably 8 ormore carbon atoms.

The general formula (Z_(IC1)) will be described below.

In the general formula (Z_(IC1)),

the definition of R and preferred scope thereof are the same as in thegeneral formula (I).

Each of R₂₀₄ and R₂₀₅ independently represents an aryl group, an alkylgroup or a cycloalkyl group.

The aryl group represented by R₂₀₄ and R₂₀₅ is preferably a phenyl groupor a naphthyl group, more preferably a phenyl group. The aryl grouprepresented by R₂₀₄ and R₂₀₅ may be one having a heterocyclic structurecontaining an oxygen atom, a nitrogen atom, a sulfur atom, etc. As thearyl group having a heterocyclic structure, a pyrrole residue (groupformed by loss of one hydrogen atom from pyrrole), a furan residue(group formed by loss of one hydrogen atom from furan), a thiopheneresidue (group formed by loss of one hydrogen atom from thiophene), anindole residue (group formed by loss of one hydrogen atom from indole),a benzofuran residue (group formed by loss of one hydrogen atom frombenzofuran), and a benzothiophene residue (group formed by loss of onehydrogen atom from benzothiophene) can be exemplified.

The alkyl group and cycloalkyl group represented by R₂₀₄ and R₂₀₅ ispreferably a linear or branched alkyl group having 1 to 10 carbon atoms(for example, a methyl group, an ethyl group, a propyl group, a butylgroup or a pentyl group) or a cycloalkyl group having 3 to 10 carbonatoms (a cyclopentyl group, a cyclohexyl group or a norbornyl group).

The aryl group, alkyl group or cycloalkyl group represented by R₂₀₄ andR₂₀₅ may have a substituent. As the substituent optionally contained inthe aryl group, alkyl group or cycloalkyl group represented by R₂₀₄ andR₂₀₅, an alkyl group (having, for example, 1 to 15 carbon atoms), acycloalkyl group (having, for example, 3 to 15 carbon atoms), an arylgroup (having, for example, 6 to 15 carbon atoms), an alkoxy group(having, for example, 1 to 15 carbon atoms), a halogen atom, a hydroxygroup, and a phenylthio group can be exemplified.

Specific examples of the compounds represented by the general formula(I) are shown below.

The acid generators can be used either individually or in combination.

The content of the acid generators in the actinic ray-sensitive orradiation-sensitive resin composition based on the total solids of theactinic ray-sensitive or radiation-sensitive resin composition ispreferably in the range of 0.1 to 40 mass %, more preferably 0.5 to 30mass %, and still more preferably 1 to 25 mass %.

[Solvent]

The photosensitive composition according to the present invention maycontain a solvent. The solvent is not limited as long as it can be usedin the preparation of a positive resist composition through dissolutionof the above-mentioned components. As the solvent, an organic solventsuch as an alkylene glycol monoalkyl ether carboxylate, an alkyleneglycol monoalkyl ether, an alkyl lactate, an alkyl alkoxypropionate, acyclolactone (preferably having 4 to 10 carbon atoms), an optionallycyclized monoketone compound (preferably having 4 to 10 carbon atoms),an alkylene carbonate, an alkyl alkoxyacetate and an alkyl pyruvate canbe exemplified.

As preferred alkylene glycol monoalkyl ether carboxylates, propyleneglycol monomethyl ether acetate, propylene glycol monoethyl etheracetate, propylene glycol monopropyl ether acetate, propylene glycolmonobutyl ether acetate, propylene glycol monomethyl ether propionate,propylene glycol monoethyl ether propionate, ethylene glycol monomethylether acetate, and ethylene glycol monoethyl ether acetate can beexemplified.

As preferred alkylene glycol monoalkyl ethers, propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmonopropyl ether, propylene glycol monobutyl ether, ethylene glycolmonomethyl ether, and ethylene glycol monoethyl ether can beexemplified.

As preferred alkyl lactates, methyl lactate, ethyl lactate, propyllactate and butyl lactate can be exemplified.

As preferred alkyl alkoxypropionates, ethyl 3-ethoxypropionate, methyl3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl3-methoxypropionate can be exemplified.

As preferred cyclolactones, β-propiolactone, β-butyrolactone,γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone,γ-valerolactone, γ-caprolactone, γ-octanoic lactone, andα-hydroxy-γ-butyrolactone can be exemplified.

As preferred optionally cyclized monoketone compounds, 2-butanone,3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-methyl-3-pentanone,4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone,2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone,5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone,2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone,3-decanone, 4-decanone, 5-hexen-2-one, 3-penten-2-one, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone,2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,4-ethylcyclohexanone, 2,2-dimethylcyclohexanone,2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone,2-methylcycloheptanone, and 3-methylcycloheptanone can be exemplified.

As preferred alkylene carbonates, propylene carbonate, vinylenecarbonate, ethylene carbonate, and butylene carbonate can beexemplified.

As preferred alkyl alkoxyacetates, acetic acid 2-methoxyethyl ester,acetic acid 2-ethoxyethyl ester, acetic acid 2-(2-ethoxyethoxy)ethylester, acetic acid 3-methoxy-3-methylbutyl ester, and acetic acid1-methoxy-2-propyl ester can be exemplified.

As preferred alkyl pyruvates, methyl pyruvate, ethyl pyruvate and propylpyruvate can be exemplified.

As a preferably employable solvent, a solvent having a boiling pointmeasured at ordinary temperature under ordinary pressure of 130° C. orabove can be mentioned. As the solvent, cyclopentanone, γ-butyrolactone,cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate,propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate,ethyl pyruvate, acetic acid 2-ethoxyethyl ester, acetic acid2-(2-ethoxyethoxy)ethyl ester, and propylene carbonate can beexemplified.

In the present invention, these solvents may be used either individuallyor in combination.

In the present invention, a mixed solvent consisting of a mixture of asolvent having a hydroxy group in its structure and a solvent having nohydroxy group may be used as the organic solvent.

As the solvent having a hydroxy group, ethylene glycol, ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, propylene glycol,propylene glycol monomethyl ether, propylene glycol monoethyl ether, andethyl lactate can be exemplified. Of these, propylene glycol monomethylether, and ethyl lactate are especially preferred.

As the solvent having no hydroxy group, propylene glycol monomethylether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone,cyclohexanone, butyl acetate, N-methylpyrrolidone,N,N-dimethylacetamide, and dimethyl sulfoxide can be exemplified. Ofthese, propylene glycol monomethyl ether acetate, ethylethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butylacetate are especially preferred. Among them, propylene glycolmonomethyl ether acetate, ethyl ethoxypropionate and 2-heptanone aremost preferred.

The mixing ratio (in terms of mass) between a solvent having a hydroxygroup and a solvent having no hydroxy group is in the range of 1/99 to99/1, preferably 10/90 to 90/10, and more preferably 20/80 to 60/40. Themixed solvent containing 50 mass % or more of a solvent having nohydroxy group is especially preferred from the viewpoint of uniformapplicability.

It is preferred for the solvent to be a mixed solvent consisting of twoor more solvents and to contain propylene glycol monomethyl etheracetate.

[Basic Compound]

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention preferably contains a basic compoundso as to decrease performance alteration over time from exposure toheating.

As preferred basic compounds, the compounds having the structuresrepresented by the following formulae (A) to (E) can be exemplified.

In the general formulae (A) and (E),

R²⁰⁰, R²⁰¹ and R²⁰² may be identical to or different from each other andeach represents a hydrogen atom, an alkyl group (preferably having 1 to20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbonatoms) or an aryl group (having 6 to 20 carbon atoms). R²⁰¹ and R²⁰² maybe bonded to each other to form a ring.

R²⁰³, R²⁰⁴, R²⁰⁵ and R²⁰⁶ may be identical to or different from eachother and each represents an alkyl group having 1 to 20 carbon atoms.

With respect to the above alkyl group, as a preferred substituted alkylgroup, an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkylgroup having 1 to 20 carbon atoms, and a cyanoalkyl group having 1 to 20carbon atoms can be exemplified.

More preferably, the alkyl groups in the general formulae (A) and (E)are unsubstituted.

As preferred compounds, guanidine, aminopyrrolidine, pyrazole,pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine andpiperidine can be exemplified. As more preferred compounds, those withan imidazole structure, a diazabicyclo structure, an onium hydroxidestructure, an onium carboxylate structure, a trialkylamine structure, ananiline structure or a pyridine structure, alkylamine derivatives havinga hydroxy group and/or an ether bond, and aniline derivatives having ahydroxy group and/or an ether bond can be exemplified.

As the compounds with an imidazole structure, imidazole,2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzoimidazole canbe exemplified. As the compounds with a diazabicyclo structure,1,4-diazabicyclo[2,2,2]octane, 1,5-diazabicyclo[4,3,0]non-5-ene, and1,8-diazabicyclo[5,4,0]undec-7-ene can be exemplified. As the compoundswith an onium hydroxide structure, tetrabutylammonium hydroxide,triarylsulfonium hydroxide, phenacylsulfonium hydroxide, and sulfoniumhydroxides having a 2-oxoalkyl group, such as triphenylsulfoniumhydroxide, tris(t-butylphenyl)sulfonium hydroxide,bis(t-butylphenyl)iodonium hydroxide, phenacylthiophenium hydroxide, and2-oxopropylthiophenium hydroxide can be exemplified. As the compoundswith an onium carboxylate structure, those having a carboxylate at theanion moiety of the compounds with an onium hydroxide structure, such asacetate, adamantane-1-carboxylate, and perfluoroalkyl carboxylate can beexemplified. As the compounds with a trialkylamine structure,tri(n-butyl)amine and tri(n-octyl)amine can be exemplified. As theaniline compounds, 2,6-diisopropylaniline, N,N-dimethylaniline,N,N-dibutylaniline, and N,N-dihexylaniline can be exemplified. As thealkylamine derivatives having a hydroxy group and/or an ether bond,ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine,and tris(methoxyethoxyethyl)amine can be exemplified. As the anilinederivatives having a hydroxy group and/or an ether bond,N,N-bis(hydroxyethyl)aniline can be exemplified.

As preferred basic compounds, an amine compound having a phenoxy group,an ammonium salt compound having a phenoxy group, an amine compoundhaving a sulfonic ester group, and an ammonium salt compound having asulfonic ester group can further be exemplified.

As the amine compound, use can be made of primary, secondary andtertiary amine compounds. An amine compound having its at least onealkyl group bonded to the nitrogen atom thereof is preferred. Among theamine compounds, a tertiary amine compound is more preferred. In theamine compounds, as long as at least one alkyl group (preferably having1 to 20 carbon atoms) is bonded to the nitrogen atom, a cycloalkyl group(preferably having 3 to 20 carbon atoms) or an aryl group (preferablyhaving 6 to 12 carbon atoms) besides the alkyl group may be bonded tothe nitrogen atom. In the amine compounds, it is preferred for the alkylchain to contain an oxygen atom to form an oxyalkylene group. The numberof oxyalkylene groups in each molecule is one or more, preferably 3 to9, and more preferably 4 to 6. The oxyalkylene group is preferably anoxyethylene group (—CH₂CH₂O—) or an oxypropylene group (—CH(CH₃)CH₂O— or—CH₂CH₂CH₂O—), more preferably an oxyethylene group (—CH₂CH₂O—).

As the ammonium salt compound, use can be made of primary, secondary,tertiary and quaternary ammonium salt compounds. An ammonium saltcompound having its at least one alkyl group bonded to the nitrogen atomthereof is preferred. Of the ammonium salt compounds, as long as atleast one alkyl group (preferably having 1 to 20 carbon atoms) is bondedto the nitrogen atom, a cycloalkyl group (preferably having 3 to 20carbon atoms) or an aryl group (preferably having 6 to 12 carbon atoms)besides the alkyl group may be bonded to the nitrogen atom. Of theammonium salt compounds, it is preferred for the alkyl chain to containan oxygen atom to form an oxyalkylene group. The number of oxyalkylenegroups in each molecule is one or more, preferably 3 to 9, and morepreferably 4 to 6. The oxyalkylene group is preferably an oxyethylenegroup (—CH₂CH₂O—) or an oxypropylene group (—CH(CH₃)CH₂O— or—CH₂CH₂CH₂O—), more preferably an oxyethylene group (—CH₂CH₂O—).

As the anion of the ammonium salt compounds, a halide, a sulfonate, aborate and a phosphate can be exemplified. Of these, a halide and asulfonate are preferred. Among halides, a chloride, a bromide and aniodide are especially preferred. Among sulfonates, an organic sulfonatehaving 1 to 20 carbon atoms is especially preferred. As the organicsulfonate, an aryl sulfonate and an alkyl sulfonate having 1 to 20carbon atoms can be exemplified. The alkyl group of the alkyl sulfonatemay have a substituent. As the substituent, a fluorine atom, a chlorineatom, a bromine atom, an alkoxy group, an acyl group, and an aryl groupcan be exemplified. As specific examples of the alkyl sulfonates,methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate,octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate,pentafluoroethane sulfonate, and nonafluorobutane sulfonate can beexemplified. As the aryl group of the aryl sulfonate, a benzene ring, anaphthalene ring, and an anthracene ring can be exemplified. The benzenering, naphthalene ring or anthracene ring may have a substituent. Aspreferred substituents, a linear or branched alkyl group having 1 to 6carbon atoms and a cycloalkyl group having 3 to 6 carbon atoms can beexemplified. As specific examples of the linear or branched alkyl groupsand cycloalkyl groups, methyl, ethyl, n-propyl, isopropyl, n-butyl,i-butyl, t-butyl, n-hexyl, and cyclohexyl group can be exemplified. Asother substituents, an alkoxy group having 1 to 6 carbon atoms, ahalogen atom, a cyano group, a nitro group, an acyl group, and anacyloxy group can be exemplified.

The amine compound having a phenoxy group and ammonium salt compoundhaving a phenoxy group are those having a phenoxy group at the oppositeend of the alkyl group to the nitrogen atom of the amine compound orammonium salt compound. The phenoxy group may have a substituent. As thesubstituent of the phenoxy group, an alkyl group, an alkoxy group, ahalogen atom, a cyano group, a nitro group, a carboxy group, acarboxylic ester group, a sulfonic ester group, an aryl group, anaralkyl group, an acyloxy group, and an aryloxy group can beexemplified. The substitution position of the substituent may be any of2- to 6-positions. The number of substituents is optional within therange of 1 to 5.

It is preferred that at least one oxyalkylene group exist between thephenoxy group and the nitrogen atom. The number of oxyalkylene groups ineach molecule is one or more, preferably 3 to 9, and more preferably 4to 6. The oxyalkylene group is preferably an oxyethylene group(—CH₂CH₂O—) or an oxypropylene group (—CH(CH₃)CH₂O— or —CH₂CH₂CH₂O—),more preferably an oxyethylene group (—CH₂CH₂O—).

The sulfonic ester group of the amine compound having a sulfonic estergroup or ammonium salt compound having a sulfonic ester group may be anyof an alkylsulfonic ester group, a cycloalkylsulfonic ester group, andan arylsulfonic ester group. In the alkylsulfonic ester group, the alkylgroup preferably has 1 to 20 carbon atoms. In the cycloalkylsulfonicester group, the cycloalkyl group preferably has 3 to 20 carbon atoms.In the arylsulfonic ester group, the aryl group preferably has 6 to 12carbon atoms. The alkylsulfonic ester group, cycloalkylsulfonic estergroup, and arylsulfonic ester group may have substituents. As preferredsubstituents, a halogen atom, a cyano group, a nitro group, a carboxygroup, a carboxylic ester group and a sulfonic ester group can beexemplified.

It is preferred that at least one oxyalkylene group exist between thesulfonic ester group and the nitrogen atom. The number of oxyalkylenegroups in each molecule is one or more, preferably 3 to 9, and morepreferably 4 to 6. The oxyalkylene group is preferably an oxyethylenegroup (—CH₂CH₂O—) or an oxypropylene group (—CH(CH₃)CH₂O— or—CH₂CH₂CH₂O—), more preferably an oxyethylene group (—CH₂CH₂O—).

These basic compounds are used either individually or in combination.

The amount of basic compound used based on the solid contents of theactinic ray-sensitive or radiation-sensitive resin composition isgenerally in the range of 0.001 to 10 mass %, preferably 0.01 to 5 mass%.

The molar ratio of the acid generator to basic compound used in thecomposition is preferably in the range of 2.5 to 300. The molar ratio ispreferred to be 2.5 or higher from the viewpoint of sensitivity andresolving power. The molar ratio is preferred to be 300 or below fromthe viewpoint of the inhibition of any resolving power deterioration dueto thickening of resist pattern over time from exposure to heatingtreatment. The ratio of acid generator/basic compound is more preferablyin the range of 5.0 to 200, and still more preferably 7.0 to 150.

[Surfactant]

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention preferably further contains asurfactant, and more preferably contains any one, or two or moremembers, of fluorinated and/or siliconized surfactants (fluorinatedsurfactant, siliconized surfactant, and surfactant containing bothfluorine and silicon atoms).

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention when containing the above surfactantwould, in the use of an exposure light source of 250 nm or below,especially 220 nm or below, realize favorable sensitivity and resolvingpower and produce a resist pattern with less adhesion and developmentdefects.

As the fluorinated and/or siliconized surfactants, those described inJP-A's-62-36663, 61-226746, 61-226745, 62-170950, 63-34540, 7-230165,8-62834, 9-54432, 9-5988 and 2002-277862 and U.S. Pat. Nos. 5,405,720,5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511 and5,824,451 can be exemplified. Any of the following commerciallyavailable surfactants can be used as is.

As useful commercially available surfactants, fluorinated surfactants orsiliconized surfactants, such as Eftop EF301 and EF303 (produced byShin-Akita Kasei Co., Ltd.), Florad FC 430, 431 and 4430 (produced bySumitomo 3M Ltd.), Megafac F171, F173, F176, F189, F113, F110, F177,F120 and R08 (produced by Dainippon Ink & Chemicals, Inc.), SurflonS-382, SC101, 102, 103, 104, 105 and 106 (produced by Asahi Glass Co.,Ltd.), Troy Sol S-366 (produced by Troy Chemical Co., Ltd.), GF-300 andGF-150 (produced by TOAGOSEI CO., LTD.), Sarfron S-393 (produced bySEIMI CHEMICAL CO., LTD.), Eftop EF121, EF122A, EF122B, RF122C, EF125M,EF135M, EF351, EF352, EF801, EF802 and EF601 (produced by JEMCO INC.),PF636, PF656, PF6320 and PF6520 (produced by OMNOVA), and FTX-204G,208G, 218G, 230G, 204D, 208D, 212D, 218D and 222D (produced by NEOS) canbe exemplified. Further, polysiloxane polymer KP-341 (produced byShin-Etsu Chemical Co., Ltd.) can be employed as the siliconizedsurfactant.

As the surfactant, besides the above publicly known surfactants, use canbe made of a surfactant based on a polymer having a fluorinatedaliphatic group derived from a fluorinated aliphatic compound, producedby a telomerization technique (also called a telomer process) or anoligomerization technique (also called an oligomer process). Thefluorinated aliphatic compound can be synthesized by the processdescribed in JP-A-2002-90991.

The polymer having a fluorinated aliphatic group is preferably acopolymer from a monomer having a fluorinated aliphatic group and apoly(oxyalkylene) acrylate and/or poly(oxyalkylene) methacrylate, inwhich copolymer may have an irregular distribution or may result fromblock copolymerization. As the poly(oxyalkylene) group, apoly(oxyethylene) group, a poly(oxypropylene) group, and apoly(oxybutylene) group can be exemplified. Further, use can be made ofa unit having alkylene groups of different chain lengths in a singlechain, such as poly(oxyethylene-oxypropylene-oxyethylene blockconcatenation) or poly(oxyethylene-oxypropylene block concatenation).Moreover, the copolymer from a monomer having a fluorinated aliphaticgroup and a poly(oxyalkylene) acrylate (or methacrylate) is not limitedto two-monomer copolymers and may be a three or more monomer copolymerobtained by simultaneous copolymerization of two or more differentmonomers having a fluorinated aliphatic group, two or more differentpoly(oxyalkylene) acrylates (or methacrylates), etc.

As a commercially available surfactant, Megafac F178, F-470, F-473,F-475, F-476 and F-472 (produced by Dainippon Ink & Chemicals, Inc.) canbe exemplified. A copolymer from an acrylate (or methacrylate) having aC₆F₁₃ group and a poly(oxyalkylene) acrylate (or methacrylate); and acopolymer from an acrylate (or methacrylate) having a C₃F₇ group,poly(oxyethylene) acrylate (or methacrylate), and poly(oxypropylene)acrylate (or methacrylate) can further be exemplified.

In the present invention, surfactants other than the fluorinated and/orsiliconized surfactants can also be employed. Specifically, nonionicsurfactants including a polyoxyethylene alkyl ether such aspolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether or polyoxyethylene oleyl ether, apolyoxyethylene alkylaryl ether such as polyoxyethylene octylphenolether or polyoxyethylene nonylphenol ether, apolyoxyethylene-polyoxypropylene block copolymer, a sorbitan fatty acidester such as sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonostearate, sorbitan monooleate, sorbitan trioleate or sorbitantristearate, and a polyoxyethylene sorbitan fatty acid ester such aspolyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate or polyoxyethylene sorbitan tristearate can beexemplified.

These surfactants may be used either individually or in combination.

The amount of each surfactant used based on the total mass of theactinic ray-sensitive or radiation-sensitive resin composition(excluding the solvent) is preferably in the range of 0 to 2 mass %,more preferably 0.0001 to 2 mass %, and most preferably 0.0005 to 1 mass%.

[Carboxylic Acid Onium Salt]

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention may contain a carboxylic acid oniumsalt. As the carboxylic acid onium salt, a carboxylic acid sulfoniumsalt, a carboxylic acid iodonium salt, and a carboxylic acid ammoniumsalt can be exemplified. The especially preferred carboxylic acid oniumsalts are the iodonium salt and the sulfonium salt. It is preferred forthe carboxylate residue of the carboxylic acid onium salt for use in thepresent invention to be one containing neither an aromatic group nor acarbon-carbon double bond. In particular, the especially preferred anionmoiety thereof is a linear, branched, monocyclic or polycyclicalkylcarboxylate anion having 1 to 30 carbon atoms. A more preferredanion moiety is an anion of carboxylic acid wherein the alkyl group ispartially or wholly fluorinated. The alkyl chain may contain an oxygenatom. Accordingly, there would be achieved securement of thetransparency in 220 nm or shorter light, enhancement of the sensitivityand resolving power, and improvement of the dependency on densitydistribution and exposure margin.

As the fluorinated carboxylic acid anion, any of the anions offluoroacetic acid, difluoroacetic acid, trifluoroacetic acid,pentafluoropropionic acid, heptafulorobutyric acid, nonafluoropentanoicacid, perfluorododecanoic acid, perfluorotridecanoic acid,perfluorocyclohexanecarboxylic acid, and 2,2-bistrifluoromethylpropionicacid can be exemplified.

These carboxylic acid onium salts can be synthesized by reacting asulfonium hydroxide, an iodonium hydroxide or an ammonium hydroxide anda carboxylic acid with silver oxide in an appropriate solvent.

The content of each carboxylic acid onium salt in the composition basedon the total solids of the composition is generally in the range of 0.1to 20 mass %, preferably 0.5 to 10 mass %, and still more preferably 1to 7 mass %.

[Dissolution Inhibiting Compound]

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention may contain a dissolution inhibitingcompound of 3000 or less molecular weight that is decomposed by theaction of an acid to increase the solubility in an alkali developer(hereinafter referred to as “dissolution inhibiting compound”).

From the viewpoint of preventing lowering of the transmission at thewavelength of 220 nm or shorter, the dissolution inhibiting compound ispreferably an alicyclic or aliphatic compound having anacid-decomposable group, such as any of cholic acid derivatives havingan acid-decomposable group described in Proceeding of SPIE, 2724, 355(1996). The acid-decomposable group and alicyclic structure can be thesame as described with respect to the resin as the component (A).

When the actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention is exposed to a KrF excimer laser orirradiated with electron beams, preferred use is made of one having astructure resulting from substitution of the phenolic hydroxy group of aphenol compound with an acid-decomposable group. The phenol compoundpreferably contains 1 to 9 phenol skeletons, more preferably 2 to 6phenol skeletons.

In the present invention, the molecular weight of the dissolutioninhibiting compound is 3000 or less, preferably in the range of 300 to3000, and more preferably 500 to 2500.

The amount of dissolution inhibiting compound added based on the totalsolids of the actinic ray-sensitive or radiation-sensitive resincomposition is preferably in the range of 3 to 50 mass %, morepreferably 5 to 40 mass %.

Specific examples of the dissolution inhibiting compounds will be shownbelow, which however in no way limit the scope of the present invention.

[Other Additives]

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention may further contain a dye, aplasticizer, a photosensitizer, a light absorber, a compound capable ofincreasing the solubility in a developer (for example, a phenoliccompound of 1000 or less molecular weight or a carboxylated alicyclic oraliphatic compound), etc.

The above phenolic compound of 1000 or less molecular weight can beeasily synthesized by persons of ordinary skill in the art whileconsulting the processes described in, for example, JP-As 4-122938 and2-28531, U.S. Pat. No. 4,916,210, and EP 219294.

As the nonlimiting examples of the carboxylated alicyclic or aliphaticcompound, a carboxylic acid derivative of steroid structure such ascholic acid, deoxycholic acid or lithocholic acid, anadamantanecarboxylic acid derivative, adamantanedicarboxylic acid,cyclohexanecarboxylic acid, and cyclohexanedicarboxylic acid can beexemplified.

[Method of Forming Pattern]

From the viewpoint of enhancement of resolving power, it is preferredfor the actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention to be used with a coating thicknessof 30 nm to 250 nm. More preferably, the actinic ray-sensitive orradiation-sensitive resin composition is used with a coating thicknessof 30 to 200 nm. This coating thickness can be attained by setting thesolid content of the actinic ray-sensitive or radiation-sensitive resincomposition within an appropriate range so as to cause the compositionto have an appropriate viscosity, thereby improving the applicabilityand film forming property.

The total solids concentration of the actinic ray-sensitive orradiation-sensitive resin composition is generally in the range of 1 to10 mass %, preferably 1 to 8.0 mass %, and more preferably 1.0 to 6.0mass %.

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to the present invention is used in such a manner that theabove components are dissolved in a given organic solvent, preferablythe above mixed solvent, and filtered and applied onto a given supportin the following manner. The filter medium for the filtration preferablyconsists of a polytetrafluoroethylene, polyethylene or nylon having apore size of 0.1 μm or less, preferably 0.05 μm or less, and morepreferably 0.03 μm or less.

For example, an actinic ray-sensitive or radiation-sensitive resincomposition is applied onto a substrate, such as one for use in theproduction of precision integrated circuit elements (e.g.,silicon/silicon dioxide coating), by appropriate application means, suchas a spinner or coater, and dried to form a film.

The film is exposed through a given mask to actinic rays or radiation,preferably baked (heated), developed, and rinsed. Accordingly, adesirable pattern can be obtained.

As the actinic rays or radiation, infrared rays, visible light,ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays,X-rays, and electron beams can be exemplified. Among them, preferred useis made of far ultraviolet rays with wavelength of preferably 250 nm orless, more preferably 220 nm or less, and still more preferably 1 to 200nm, such as a KrF excimer laser (248 nm), an ArF excimer laser (193 nm)and an F2 excimer laser (157 nm), as well as X-rays, and electron beams.More preferred use is made of an ArF excimer laser, an F2 excimer laser,EUV (13 nm) and electron beams.

Prior to the formation of a resist film, the substrate may be coatedwith an anti-reflection film.

As the anti-reflection film, use can be made of not only an inorganicfilm of titanium, titanium oxide, titanium nitride, chromium oxide,carbon, amorphous silicon or the like but also an organic film composedof a light absorber and a polymer material. Also, as the organicanti-reflection film, use can be made of commercially available organicanti-reflection films, such as the DUV30 Series and DUV40 Seriesproduced by Brewer Science Inc. and AR-2, AR-3 and AR-5 produced byShipley Co., Ltd.

In the step for development, an alkali developer is used as in thefollowings. As the alkali developer for an actinic ray-sensitive orradiation-sensitive resin composition, use can be made of any ofalkaline aqueous solutions of an inorganic alkali such as sodiumhydroxide, potassium hydroxide, sodium carbonate, sodium silicate,sodium metasilicate or aqueous ammonia, a primary amine such asethylamine or n-propylamine, a secondary amine such as diethylamine ordi-n-butylamine, a tertiary amine such as triethylamine ormethyldiethylamine, an alcoholamine such as dimethylethanolamine ortriethanolamine, a quaternary ammonium salt such as tetramethylammoniumhydroxide or tetraethylammonium hydroxide, a cycloamine such as pyrroleor piperidine, etc.

Before the use of the above alkali developer, appropriate amounts of analcohol and a surfactant may be added thereto.

The alkali concentration of the alkali developer is generally in therange of 0.1 to 20 mass %.

The pH value of the alkali developer is generally in the range of 10.0to 15.0.

Before the use of the above alkaline aqueous solution, appropriateamounts of an alcohol and a surfactant may be added thereto.

Pure water can be used as the rinse liquid. Before the use, anappropriate amount of surfactant may be added thereto.

The development operation or rinse operation may be followed by theoperation for removing any developer or rinse liquid adhering onto thepattern by the use of a supercritical fluid.

At the time of irradiation with actinic rays or radiation, exposure(liquid immersion exposure) may be carried out after filling theinterstice between resist film and lens with a liquid (liquid immersionmedium, liquid for liquid immersion) of refractive index higher thanthat of air. This would bring about an enhancement of resolving power.Any liquid with a refractive index higher than that of air can beemployed as the liquid immersion medium. Preferably, pure water isemployed.

The liquid for liquid immersion for use in the liquid immersion exposurewill now be described.

The liquid for liquid immersion preferably consists of a liquid beingtransparent in exposure wavelength whose temperature coefficient ofrefractive index is as low as possible so as to ensure minimization ofany distortion of optical image projected on the resist film. Especiallyin the use of an ArF excimer laser (wavelength: 193 nm) as an exposurelight source, however, it is more preferred to use water from not onlythe above viewpoints but also the viewpoints of easy procurement andeasy handling.

Further, from the viewpoint of refractive index increase, use can bemade of a medium of 1.5 or higher refractive index. Such a medium may beeither an aqueous solution or an organic solvent.

In the use of water as a liquid for liquid immersion, a slightproportion of additive (liquid) that would not dissolve the resist filmon a wafer and would be negligible with respect to its influence on anoptical coat for an under surface of lens element may be added in orderto not only decrease the surface tension of water but also increase asurface activating power. The additive is preferably an aliphaticalcohol with a refractive index approximately equal to that of water,for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. Theaddition of an alcohol with a refractive index approximately equal tothat of water is advantageous in that even when the alcohol component isevaporated from water to cause a change of content concentration, thechange of refractive index of the liquid as a whole can be minimized. Onthe other hand, when a substance being opaque in 193 nm rays or animpurity whose refractive index is greatly different from that of wateris mixed therein, the mixing would invite a distortion of optical imageprojected on the resist film. Accordingly, it is preferred to usedistilled water as the liquid immersion water. Furthermore, use may bemade of pure water having been filtered through, for example, an ionexchange filter.

Desirably, the electrical resistance of the water is 18.3 MQcm orhigher, and the TOC (organic matter concentration) thereof is 20 ppb orbelow. Prior deaeration of the water is desired.

Raising the refractive index of the liquid for liquid immersion wouldenable an enhancement of lithography performance. From this viewpoint,an additive suitable for refractive index increase may be added to thewater. Alternatively, heavy water (D₂O) may be used in place of water.

In the exposure of the resist film of the actinic ray-sensitive orradiation-sensitive resin composition according to the present inventionvia the liquid immersion medium, a hydrophobic resin (HR) may further beadded. This would bring about uneven localization of the hydrophobicresin (HR) on the surface layer of the film. When the liquid immersionmedium is water, there would be attained an improvement of recedingcontact angle on the surface of the film with reference to water uponformation of the resist film, and accordingly an enhancement of theliquid immersion water tracking property. Although the hydrophobic resin(HR) is not particularly limited as long as an improvement of recedingcontact angle on the surface is realized by the addition thereof, it ispreferred to employ a resin having at least either a fluorine atom or asilicon atom. The receding contact angle of the film is preferably inthe range of 60° to 90°, more preferably 70° or higher. The amount ofresin added can be appropriately regulated so that the receding contactangle of the film falls within the above range. However, the additionamount based on the total solids of the actinic ray-sensitive orradiation-sensitive resin composition is preferably in the range of 0.1to 10 mass %, more preferably 0.1 to 5 mass %. Although the hydrophobicresin (HR) is unevenly localized on the interface as aforementioned,differing from the surfactant, the hydrophobic resin does not have tobring a hydrophilic group in its molecule and does not need tocontribute toward uniform mixing of polar/nonpolar substances.

The receding contact angle refers to a contact angle determined when thecontact line at a droplet-substrate interface draws back. It isgenerally known that the receding contact angle is useful in thesimulation of droplet mobility in a dynamic condition. In a simpledefinition, the receding contact angle can be defined as the contactangle exhibited at the recession of the droplet interface at the timeof, after application of a droplet discharged from a needle tip onto asubstrate, re-indrawing the droplet into the needle. Generally, thereceding contact angle can be measured according to a method of contactangle measurement known as the dilation/contraction method.

In the operation of liquid immersion exposure, it is needed for theliquid for liquid immersion to move on a wafer while tracking themovement of an exposure head involving high-speed scanning on the waferand thus forming an exposure pattern. Therefore, the contact angle ofthe liquid for liquid immersion with respect to the film in dynamiccondition is important, and it is required for the actinic ray-sensitiveor radiation-sensitive resin composition to be capable of tracking thehigh-speed scanning of the exposure head without leaving droplets.

The fluorine atom and/or silicon atom in the hydrophobic resin (HR) maybe present in the principal chain of the resin or may be a substituenton the side chain thereof.

The hydrophobic resin (HR) is preferably a resin having as a partialstructure containing a fluorine atom an alkyl group containing afluorine atom, a cycloalkyl group containing a fluorine atom, or an arylgroup containing a fluorine atom.

The alkyl group containing a fluorine atom (preferably having 1 to 10carbon atoms, more preferably 1 to 4 carbon atoms) is a linear orbranched alkyl group having at least one hydrogen atom thereofsubstituted with a fluorine atom. Further, other substituents may alsobe contained.

The cycloalkyl group containing a fluorine atom is a monocyclic orpolycyclic alkyl group having at least one hydrogen atom thereofsubstituted with a fluorine atom. Further, other substituents may alsobe contained.

As the aryl group containing a fluorine atom, those having at least onehydrogen atom of an aryl group, such as a phenyl or naphthyl group,substituted with a fluorine atom can be exemplified. Further, othersubstituents may also be contained.

As preferred alkyl groups containing a fluorine atom, cycloalkyl groupscontaining a fluorine atom and aryl groups containing a fluorine atom,groups of the following general formulae (F2) to (F4) can beexemplified, which however in no way limit the scope of the presentinvention.

In the general formulae (F2) to (F4),

each of R₅₇ to R₆₈ independently represents a hydrogen atom, a fluorineatom or an alkyl group, in condition that at least one of each ofR₅₇-R₆₁, R₆₂-R₆₄ and R₆₅-R₆₈ represents a fluorine atom or an alkylgroup (preferably having 1 to 4 carbon atoms) having at least onehydrogen atom thereof substituted with a fluorine atom. It is preferredthat all of R₅₇-R₆₁ and R₆₅-R₆₇ represent fluorine atoms. Each of R₆₂,R₆₃ and R₆₈ preferably represents an alkyl group (preferably having 1 to4 carbon atoms) having at least one hydrogen atom thereof substitutedwith a fluorine atom, more preferably a perfluoroalkyl group having 1 to4 carbon atoms. R₆₂ and R₆₃ may be bonded to each other to form a ring.

Specific examples of the groups represented by the general formula (F2)include a p-fluorophenyl group, a pentafluorophenyl group, and a3,5-di(trifluoromethyl)phenyl group.

Specific examples of the groups represented by the general formula (F3)include a trifluoromethyl group, a pentafluoropropyl group, apentafluoroethyl group, a heptafluorobutyl group, a hexafluoroisopropylgroup, a heptafluoroisopropyl group, a hexafluoro(2-methyl)isopropylgroup, a nonafluorobutyl group, an octafluoroisobutyl group, anonafluorohexyl group, a nonafluoro-t-butyl group, a perfluoroisopentylgroup, a perfluorooctyl group, a perfluoro(trimethyl)hexyl group, a2,2,3,3-tetrafluorocyclobutyl group, and a perfluorocyclohexyl group. Ofthese, a hexafluoroisopropyl group, a heptafluoroisopropyl group, ahexafluoro(2-methyl)isopropyl group, an octafluoroisobutyl group, anonafluoro-t-butyl group and a perfluoroisopentyl group are preferred. Ahexafluoroisopropyl group and a heptafluoroisopropyl group are morepreferred.

Specific examples of the groups represented by the general formula (F4)include —C(CF₃)₂OH, —C(C₂F₅)₂OH, —C(CF₃)(CH₃)OH, —CH(CF₃)OH and thelike. Of these, —C(CF₃)₂OH is preferred.

Specific examples of the repeating units having a fluorine atom will beshown below, which however in no way limit the scope of the presentinvention.

In the specific examples, X₁ represents a hydrogen atom, —CH₃, —F or—CF₃.

X₂ represents —F or —CF₃.

The hydrophobic resin (HR) may contain a silicon atom. As preferablepartial structure containing the silicon atom, a resin having analkylsilyl structure (preferably a trialkylsilyl group) or acyclosiloxane structure can be exemplified.

As the alkylsilyl structure or cyclosiloxane structure, any of thegroups represented by the following general formulae (CS-1) to (CS-3)can be exemplified.

In the general formulae (CS-1) to (CS-3),

each of R₁₂ to R₂₆ independently represents a linear or branched alkylgroup (preferably having 1 to 20 carbon atoms) or a cycloalkyl group(preferably having 3 to 20 carbon atoms).

Each of L₃ to L₅ represents a single bond or a bivalent connectinggroup. As the bivalent connecting group, any one or a combination of twoor more groups selected from the group consisting of an alkylene group,a phenylene group, an ether group, a thioether group, a carbonyl group,an ester group, an amido group, a urethane group and a urea group can beexemplified.

In the formulae, n is an integer of 1 to 5.

Specific examples of the repeating units having the groups representedby the general formulae (CS-1) to (CS-3) will be shown below, whichhowever in no way limit the scope of the present invention. In thespecific examples, X₁ represents a hydrogen atom, —CH₃, —F or —CF₃.

Moreover, the hydrophobic resin (HR) may have at least one groupselected from among the following groups (x) to (z):

(x) an alkali soluble group,

(y) a group that is decomposed by the action of an alkali developer,resulting in an increase of solubility in the alkali developer, and

(z) a group that is decomposed by the action of an acid.

As the alkali soluble group (x), a phenolic hydroxy group, a carboxylategroup, a fluoroalcohol group, a sulfonate group, a sulfonamido group, asulfonylimido group, an (alkylsulfonyl)(alkylcarbonyl)methylene group,an (alkylsulfonyl)(alkylcarbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylenegroup can be exemplified.

As preferred alkali soluble groups, a fluoroalcohol group (preferablyhexafluoroisopropanol group), a sulfonimido group, and abis(carbonyl)methylene group can be exemplified.

As the repeating unit having an alkali soluble group (x), preferred useis made of any of a repeating unit resulting from direct bonding of analkali soluble group to the principal chain of a resin like a repeatingunit of acrylic acid or methacrylic acid; a repeating unit resultingfrom bonding, via a connecting group, of an alkali soluble group to theprincipal chain of a resin; and a repeating unit resulting frompolymerization with the use of a chain transfer agent or polymerizationinitiator having an alkali soluble group to introduce the same in apolymer chain terminal.

The content of repeating units having an alkali soluble group (x) basedon all the repeating units of the polymer is preferably in the range of1 to 50 mol %, more preferably 3 to 35 mol %, and still more preferably5 to 20 mol %.

Specific examples of the repeating units having an alkali soluble group(x) will be shown below, which however in no way limit the scope of thepresent invention.

In the formulae, Rx represents H, CH₃, CF₃ or CH₂OH.

As the group (y) that is decomposed by the action of an alkali developerresulting in an increase of solubility in the alkali developer, a grouphaving a lactone structure, an acid anhydride group, and an acid imidegroup can be exemplified. Of these, a group having a lactone structureis preferred.

As the repeating unit having a group (y) that is decomposed by theaction of an alkali developer resulting in an increase of solubility inthe alkali developer, preferred use is made of both of a repeating unitresulting from bonding of a group (y) that is decomposed by the actionof an alkali developer resulting in an increase of solubility in thealkali developer to the principal chain of a resin such as a repeatingunit of acrylic ester or methacrylic ester, and a repeating unitresulting from polymerization with the use of a chain transfer agent orpolymerization initiator having a group (y) resulting in an increase ofsolubility in an alkali developer to introduce the same in a polymerchain terminal.

The content of repeating units having a group (y) resulting in anincrease of solubility in an alkali developer based on all the repeatingunits of the polymer is preferably in the range of 1 to 40 mol %, morepreferably 3 to 30 mol %, and still more preferably 5 to 15 mol %.

As specific examples of the repeating units having a group (y) resultingin an increase of solubility in an alkali developer, the same repeatingunits having a lactone structure as set forth with respect to thecomponent (A) can be exemplified.

As the repeating unit having a group (z) that is decomposed by theaction of an acid in the hydrophobic resin (HR), the same repeatingunits having an acid decomposable group as set forth with respect to thecomponent (A) can be exemplified. The content of repeating units havinga group (z) that is decomposed by the action of an acid in thehydrophobic resin (HR) based on all the repeating units of the polymeris preferably in the range of 1 to 80 mol %, more preferably 10 to 80mol %, and still more preferably 20 to 60 mol %.

The hydrophobic resin (HR) may further have any of the repeating unitsrepresented by the following general formula (III).

In the general formula (III),

R_(c31) represents a hydrogen atom, an alkyl group, an alkyl groupoptionally substituted with a fluorine atom, a cyano group or a group ofthe formula —CH₂—O-Rac₂ in which Rac₂ represents a hydrogen atom, analkyl group or an acyl group. R_(c31) is preferably a hydrogen atom, amethyl group, a hydroxymethyl group, or a trifluoromethyl group, morepreferably a hydrogen atom of a methyl group.

R_(c32) represents a group containing an alkyl group, a cycloalkylgroup, an alkenyl group, or a cycloalkenyl group. These groups may besubstituted with a fluorine atom or a silicon atom.

L_(c3) represents a single bond or a bivalent connecting group.

In the general formula (III), the alkyl group represented by R_(c32) ispreferably a linear or branched alkyl group having 3 to 20 carbon atoms.

The cycloalkyl group is preferably a cycloalkyl group having 3 to 20carbon atoms.

The alkenyl group is preferably an alkenyl group having 3 to 20 carbonatoms.

The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20carbon atoms.

Preferably, R_(c32) represents an unsubstituted alkyl group or an alkylgroup substituted with a fluorine atom.

The bivalent connecting group represented by L_(c) is preferably anester group, an alkylene group (preferably having 1 to 5 carbon atoms),an oxy group, or a phenylene group.

Further, the hydrophobic resin (HR) may also preferably have any of therepeating units represented by general formula (CII-AB) below.

In the general formula (CII-AB),

each of R_(c11)′ and R_(c12)′ independently represents a hydrogen atom,a cyano group, a halogen atom or an alkyl group.

Zc′ represents an atomic group for forming an alicyclic structure whichcontains two bonded carbon atoms (C—C).

Specific examples of the repeating units represented by the generalformula (III) and general formula (CII-AB) will be shown below, whichhowever in no way limit the scope of the present invention. In theformulae, Ra represents H, CH₃, CH₂OH, CF₃ or CN.

When the hydrophobic resin (HR) contains fluorine atoms, the content ofthe fluorine atoms based on the molecular weight of the hydrophobicresin (HR) is preferably in the range of 5 to 80 mass %, and morepreferably 10 to 80 mass %. The repeating unit containing fluorine atomspreferably exists in the hydrophobic resin (HR) in an amount of 10 to100 mass %, more preferably 30 to 100 mass %.

When the hydrophobic resin (HR) contains silicon atoms, the content ofthe silicon atoms based on the molecular weight of the hydrophobic resin(HR) is preferably in the range of 2 to 50 mass %, more preferably 2 to30 mass %. The repeating unit containing silicon atoms preferably existsin the hydrophobic resin (HR) in an amount of 10 to 100 mass %, morepreferably 20 to 100 mass %.

The weight average molecular weight of the hydrophobic resin (HR) interms of standard polystyrene molecular weight is preferably in therange of 1,000 to 100,000, more preferably 1,000 to 50,000, and stillmore preferably 2,000 to 15,000.

The content of the hydrophobic resin (HR) in the composition based onthe total solids thereof is preferably in the range of 0.01 to 10 mass%, more preferably 0.05 to 8 mass %, and most preferably 0.1 to mass %.

Impurities such as metals in the hydrophobic resin (HR) should naturallybe of low quantity as in the component (A). The content of residualmonomers and oligomer components is preferably in the range of 0 to mass%, more preferably 0 to 5 mass %, and still more preferably 0 to 1 mass%. Accordingly, there can be obtained a composition being free fromin-liquid foreign matters and a change in sensitivity, etc. over time.From the viewpoint of resolving power, resist profile, side wall ofresist pattern, roughness, etc., the molecular weight distribution(Mw/Mn, also referred to as the degree of dispersal) thereof ispreferably in the range of 1 to 5, more preferably 1 to 3, and stillmore preferably 1 to 2.

A variety of commercially available products can be used as thehydrophobic resin (HR), and also the resin can be synthesized inaccordance with conventional methods (for example, by radicalpolymerization). As general synthesizing methods, a batch polymerizationmethod in which a monomer species and an initiator are dissolved in asolvent and heated to carry out polymerization and a droppingpolymerization method in which a solution of monomer species andinitiator is dropped into a hot solvent over a period of 1 to 10 hourscan be exemplified. Of these, the dropping polymerization method ispreferred. As a reaction solvent, ethers such as tetrahydrofuran,1,4-dioxane or diisopropyl ether, ketones such as methyl ethyl ketone ormethyl isobutyl ketone, ester solvents such as ethyl acetate, amidesolvents such as dimethylformamide or dimethylacetamide, and theaforementioned solvent capable of dissolving the composition accordingto the present invention, such as propylene glycol monomethyl etheracetate, propylene glycol monomethyl ether or cyclohexanone can beexemplified. Preferably, the polymerization is carried out with the useof the same solvent as that used in the composition according to thepresent invention. This would inhibit particle generation duringstorage.

The polymerization reaction is preferably carried out in an atmosphereconsisting of an inert gas such as nitrogen or argon. In the initiationof polymerization, a commercially available radical initiator (azoinitiator, peroxide, etc.) is used as the polymerization initiator.Among the radical initiators, an azo initiator is preferred, and azoinitiators having an ester group, a cyano group and a carboxy group aremore preferred. As specific preferred initiators,azobisisobutyronitrile, azobisdimethylvaleronitrile, and dimethyl2,2′-azobis(2-methylpropionate) can be exemplified. The reactionconcentration is in the range of 5 to 50 mass %, preferably 30 to 50mass %. The reaction temperature is generally in the range of 10° to150° C., preferably 30° to 120° C., and more preferably 60° to 100° C.

After the completion of the reaction, the mixture is allowed to standstill to cool to room temperature and purified. In the purification, useis made of routine methods, such as a liquid-liquid extraction method inwhich residual monomers and oligomer components are removed by waterwashing or by the use of a combination of appropriate solvents, a methodof purification in solution form such as ultrafiltration capable ofextraction removal of only components of a given molecular weight orbelow, a re-precipitation method in which a resin solution is droppedinto a poor solvent to coagulate the resin in the poor solvent and thusremove residual monomers, etc. and a method of purification in solidform such as washing of a resin slurry obtained by filtration with theuse of a poor solvent. For example, the reaction solution is broughtinto contact with a solvent wherein the resin is poorly soluble orinsoluble (poor solvent) amounting to 10 or less, preferably 10 to 5times the volume of the reaction solution to precipitate the resin as asolid.

The solvent for use in the operation of precipitation orre-precipitation from a polymer solution (precipitation orre-precipitation solvent) is not limited as long as the solvent is apoor solvent for the polymer. According to the type of polymer, use canbe made of any one appropriately selected from among a hydrocarbon, ahalogenated hydrocarbon, a nitro compound, an ether, a ketone, an ester,a carbonate, an alcohol, a carboxylic acid, water, a mixed solventcontaining these solvents, and the like. Of these, it is preferred toemploy a solvent containing at least an alcohol (especially methanol orthe like) or water as the precipitation or re-precipitation solvent.

The amount of precipitation or re-precipitation solvent used can bedetermined according to intended efficiency, yield, etc. and isgenerally in the range of 100 to 10,000 parts by mass, preferably 200 to2,000 parts by mass, and more preferably 300 to 1,000 parts by mass per100 parts by mass of the polymer solution.

The temperature at which the precipitation or re-precipitation iscarried out can be determined according to efficiency and operationeasiness, and is generally in the range of about 0° to 50° C., andpreferably about room temperature (for example, about 20° to 35° C.).The operation of precipitation or re-precipitation can be carried out bya known method such as a batch or continuous method, with the use of acommon mixing vessel such as an agitation vessel.

The polymer obtained by the precipitation or re-precipitation isgenerally subjected to common solid/liquid separation, such asfiltration or centrifugal separation, and dried before use. Thefiltration is carried out with the use of a filter medium ensuringsolvent resistance, preferably under pressure. The drying is performedat about 30° C. to 100° C., preferably about 30° C. to 50° C. atordinary pressure or reduced pressure (preferably at reduced pressure).

Alternatively, after the resin precipitation and separation, theobtained resin may be once more dissolved in a solvent and brought intocontact with a solvent wherein the resin is poorly soluble or insoluble.Specifically, the method may include the steps of, after the completionof the radical polymerization reaction, bringing the polymer intocontact with a solvent wherein the polymer is poorly soluble orinsoluble to thereby precipitate a resin (step a), separating the resinfrom the solution (step b), re-dissolving the resin in a solvent tothereby obtain a resin solution (A) (step c), thereafter bringing theresin solution (A) into contact with a solvent wherein the resin ispoorly soluble or insoluble amounting to less than 10 times (preferably5 times or less) the volume of the resin solution (A) to therebyprecipitate a resin solid (step d), and separating the precipitatedresin (step e).

Specific examples of the hydrophobic resins (HR) will be shown below.The following Table 1 shows the molar ratio of individual repeatingunits (corresponding to individual repeating units in order from theleft), weight average molecular weight, and degree of dispersal withrespect to each of the resins.

TABLE 1 resin composition Mw Mw/Mn HR-1 50/50 4900 1.4 HR-2 50/50 51001.6 HR-3 50/50 4800 1.5 HR-4 50/50 5300 1.6 HR-5 50/50 4500 1.4 HR-6 1005500 1.6 HR-7 50/50 5800 1.9 HR-8 50/50 4200 1.3 HR-9 50/50 5500 1.8HR-10 40/60 7500 1.6 HR-11 70/30 6600 1.8 HR-12 40/60 3900 1.3 HR-1350/50 9500 1.8 HR-14 50/50 5300 1.6 HR-15 100 6200 1.2 HR-16 100 56001.6 HR-17 100 4400 1.3 HR-18 50/50 4300 1.3 HR-19 50/50 6500 1.6 HR-2030/70 6500 1.5 HR-21 50/50 6000 1.6 HR-22 50/50 3000 1.2 HR-23 50/505000 1.5 HR-24 50/50 4500 1.4 HR-25 30/70 5000 1.4 HR-26 50/50 5500 1.6HR-27 50/50 3500 1.3 HR-28 50/50 6200 1.4 HR-29 50/50 6500 1.6 HR-3050/50 6500 1.6 HR-31 50/50 4500 1.4 HR-32 30/70 5000 1.6 HR-33 30/30/406500 1.8 HR-34 50/50 4000 1.3 HR-35 50/50 6500 1.7 HR-36 50/50 6000 1.5HR-37 50/50 5000 1.6 HR-38 50/50 4000 1.4 HR-39 20/80 6000 1.4 HR-4050/50 7000 1.4 HR-41 50/50 6500 1.6 HR-42 50/50 5200 1.6 HR-43 50/506000 1.4 HR-44 70/30 5500 1.6 HR-45 50/20/30 4200 1.4 HR-46 30/70 75001.6 HR-47 40/58/2 4300 1.4 HR-48 50/50 6800 1.6 HR-49 100 6500 1.5 HR-5050/50 6600 1.6 HR-51 30/20/50 6800 1.7 HR-52 95/5 5900 1.6 HR-5340/30/30 4500 1.3 HR-54 50/30/20 6500 1.8 HR-55 30/40/30 7000 1.5 HR-5660/40 5500 1.7 HR-57 40/40/20 4000 1.3 HR-58 60/40 3800 1.4 HR-59 80/207400 1.6 HR-60 40/40/15/5 4800 1.5 HR-61 60/40 5600 1.5 HR-62 50/50 59002.1 HR-63 80/20 7000 1.7 HR-64 100 5500 1.8 HR-65 50/50 9500 1.9

For the prevention of direct contact of a film with a liquid for liquidimmersion, a film that is highly insoluble in the liquid for liquidimmersion (hereinafter also referred to as a “top coat”) may be providedbetween the film formed by the composition according to the presentinvention and the liquid for liquid immersion. The functions to befulfilled by the top coat are applicability to an upper layer portion ofthe film, transparency in radiation of especially 193 nm, and highinsolubility in the liquid for liquid immersion. Preferably, the topcoat does not mix with the film and is uniformly applicable to an upperlayer of the film.

From the viewpoint of transparency in radiation of 193 nm, the top coatpreferably consists of a polymer not abundantly containing an aromaticmoiety. As such, a hydrocarbon polymer, an acrylic ester polymer,polymethacrylic acid, polyacrylic acid, polyvinyl ether, a siliconizedpolymer, and a fluoropolymer can be exemplified. The aforementionedhydrophobic resins (HR) also find appropriate application in the topcoat. From the viewpoint of contamination of an optical lens by leachingof impurities from the top coat into the liquid for liquid immersion, itis preferred to reduce the amount of residual monomer components of thepolymer contained in the top coat.

At the detachment of the top coat, use may be made of a developer, or aseparate peeling agent may be used. The peeling agent preferablyconsists of a solvent having low permeation into the film. Detachabilityby an alkali developer is preferred from the viewpoint of simultaneousattainment of the detachment step with the development processing stepfor the resist film. The top coat is preferred to be acidic from theviewpoint of detachment with the use of an alkali developer. However,from the viewpoint of non-intermixability with the resist film, the topcoat may be neutral or alkaline.

The less the difference in refractive index between the top coat and theliquid for liquid immersion, the higher the resolving power. In an ArFexcimer laser (wavelength: 193 nm), when water is used as the liquid forliquid immersion, the top coat for ArF liquid immersion exposurepreferably has a refractive index close to that of the liquid for liquidimmersion. From the viewpoint of approximation of the refractive indexto that of the liquid for liquid immersion, it is preferred for the topcoat to contain a fluorine atom. From the viewpoint of transparency andrefractive index, it is preferred to reduce the thickness of the film.

Preferably, the top coat does not mix with the film and also does notmix with the liquid for liquid immersion. From this viewpoint, when theliquid for liquid immersion is water, it is preferred for the solventused in the top coat to be highly insoluble in the solvent used in theactinic ray-sensitive or radiation-sensitive resin composition and be anon-water-soluble medium. When the liquid for liquid immersion is anorganic solvent, the top coat may be soluble or insoluble in water.

EXAMPLE

The present invention will now be described in greater detail withreference to Examples, which however in no way limit the scope of thepresent invention.

Synthetic Example 1 Synthesis of Resin [1]

In a nitrogen stream, 25.5 g of cyclohexanone was placed in athree-necked flask and heated at 80° C. A solution obtained bydissolving the monomers, each corresponding to the repeating unitsconstituting the resin (1) below, amounting in order from the left sideto 2.80, 3.05, 1.26, 1.82 and 3.94 g and further a polymerizationinitiator (V601) (produced by Wako Pure Chemical Industries, Ltd., 0.81g viz. 7.0 mol % based on the monomers) in 47.4 g of cyclohexanone wasdropped thereinto over a period of 6 hours. After the completion of thedropping, reaction was allowed to continue at 80° C. for 2 hours. Thereaction mixture was allowed to stand still to cool and was dropped intoa mixed liquid consisting of 420 g of hexane and 180 g of ethyl acetateover a period of 20 min. The thus precipitated powder was collected byfiltration and dried, thereby obtaining 10 g of a polymer (1). Theweight average molecular weight (Mw) of the obtained resin (1) in termsof standard polystyrene molecular weight was 9570 and the degree ofdispersal (Mw/Mn) thereof was 1.7. The glass transition point (Tg) ofthe resin (1) as measured by a DSC (manufactured by TA Instruments) was150° C.

Resin (1) synthesized in Synthetic Example 1:

Resins (2) to (9) below for use in the present invention weresynthesized in the same manner as in Synthetic Example 1.

Furthermore, comparative resins (R1) to (R6) were synthesized in thesame manner.

<Evaluation of Hydrolysis Rate of Lactone Monomer> (Measuring Conditionsfor HPLC) Apparatus: New Shimadzu,

column: Sympack column (ODS),eluate: acetonitrile/buffer=70/30, 1 ml/min,buffer: distilled water/phosphoric acid/triethylamine=1000/1/1, anddetection: 254 nm.

(Preparation of Solution)

(A) Anisole Solution (Internal Standard)

1 g of 2,4-dimethylanisole was placed in a 50-ml measuring flask andmeasured up with acetonitrile.

(B) Lactone Sample Solution

1 mmol of a sample and 2 ml of the anisole solution (A) were placed in a10-ml measuring flask and measured up with acetonitrile.

(Measurement) (1) Measurement of Reference

0.3 ml of a sample solution and 2.7 ml of acetonitrile were placed in anHPLC sample tube and measured by HPLC.

(2) Measurement of Sample (Reaction with Alkali: Evaluation ofHydrolyzability)

0.3 ml of a sample solution and 1.2 ml of acetonitrile were placed in anHPLC sample tube, and 1.5 ml of a pH10 standard solution was addedthereto, gently shaken so as to obtain a homogeneous mixture, and thenmeasured by HPLC.

(3) Measurement of Sample (Reaction with Water: Evaluation of Stability)

The procedure of item 2 above was repeated except that water was used inplace of the pH10 standard solution.

The monomer residual ratio (%) was determined from the area ratiobetween that of the monomer and of the internal standard at eachreaction time with the employment of the area ratio at the beginning ofthe reaction as a base quantity (100%). The residual ratio of thefollowing GBL lactone at the lapse of 10 min was regarded as a standardvalue (1) and the rate of alkali hydrolysis of each of other lactoneswas defined by a relative value according to the formula given below.The greater the value, the lower the rate of hydrolysis. The smaller thevalue, the higher the rate of hydrolysis.

[relative value of the rate of alkali hydrolysis]=[residual ratio ofother lactone]/[residual ratio of reference lactone (GBL)]

TABLE 2 (relative values of the rate of alkali hydrolysis)

1

0.7

3.2

3

0.7

<0.1

2.8

3.3

<0.1

2.1

<Preparation of Resist>

The components indicated in the following Table 3 were dissolved in asolvent to obtain a solution with the solid content of each of thecomponents being 4 mass %. This solution was passed through apolyethylene filter of 0.05-μm pore size, thereby obtaining a actinicray-sensitive or radiation-sensitive resin composition. The thusobtained actinic ray-sensitive or radiation-sensitive resin compositionwas evaluated by the following methods, the results of which being givenin Table 4. Note that the ratios given in Table 3 represents the massratios thereof.

In Table 3, the addition mode is indicated as “addition” when theactinic ray-sensitive or radiation-sensitive resin composition containeda hydrophobic resin (HR). On the other hand, the addition mode isindicated as “TC” when the actinic ray-sensitive or radiation-sensitiveresin composition was free of hydrophobic resin (HR) and when afterformation of a resist film, a top coat protective film containing ahydrophobic resin (HR) was formed on an upper layer of the resist film.

TABLE 3 Photoacid Hydrophobic Resin generator Basic resin (A) (B)compound Surfactant (addition/ (3.5 g) (0.3 g) (10 mg) (10 mg) TC)Solvent (96.5 g) Ex. 1 (1) PAG- DIA W-1 addition A1/B1 = 1/PAG- HR-286/4 3 = 2/1 (30 mg)  2 (2) PAG- DIA W-1 addition A1/B1 = 2/PAG-3 = HR-476/4 1/1 (35 mg)  3 (3) PAG-4 TBAH W-2 addition A1/A3 = HR-41 95/5 (45mg)  4 (4) PAG- TMEA W-5 addition A1/B1 = 1/PAG-3 = HR-47 6/4 1/1 (20mg)  5 (5) PAG- PEA W-3 addition A1/B1 = 2/PAG-4 = HR-47 6/4 2/1 (30 mg) 6 (6) PAG- DIA W-2 addition A1/B1 = 1/PAG-4 = HR-50 6/4 1/1 (30 mg)  7(7) PAG- PEA W-4 addition A1/A2 = 1/PAG-4 = HR-47 8/2 2/1 (30 mg)  8 (8)PAG-3 PEA W-5 addition A1/B2 = HR-28 8/2 (30 mg)  9 (9) PAG- DIA W-1addition A1/B1 = 1/PAG-4 = HR-28 6/4 1/2 (30 mg) 10 (4) PAG-2 TMEA W-5addition A1/B1 = HR-40 6/4 (30 mg) 11 (4) PAG- DIA W-5 TC A1/B1 =1/PAG-4 = HR-50 6/4 1/2 Ex. (1) PAG-5 DIA — addition A1 12 HR-47 (30 mg)13 (7) PAG- DIA W-1 addition A1/A2 = 1/PAG-4 = HR-47 8/2 1/1 (15 mg)HR-28 (15 mg) 14 (8) PAG-5 DIA W-1 addition A1 HR-47 (30 mg) 15 (1)PAG-6 DIA — addition A1/B2 = HR-47 6/4 (30 mg) 16 (1) PAG-2 PEA W-2addition A1/B = HR-28 8/2 (30 mg) 17 (4) PAG-3 DIA — addition A1 HR-47(30 mg) 18 (3) PAG-2 DIA W-1 addition A1 HR-47 (15 mg) HR-56 (15 mg) 19(1) PAG- DIA W-1 addition A1/B2 = 1/PAG-3 = HR-47 8/2 1/1 (30 mg) 20 (1)PAG- DIA — addition A1 1/PAG-5 = HR-47 1/1 (30 mg) Comp. 1 R1 PAG-2 DIAW-1 addition A1/B1 = HR-41 6/4 (30 mg)  2 R2 PAG-2 TBAH W-2 additionA1/A3 = HR-41 95/5 (30 mg)  3 R3 PAG-2 PEA W-2 addition A1/A3 = HR-2895/5 (30 mg)  4 R4 PAG-2 DIA W-2 addition A1/A3 = HR-28 95/5 (30 mg)  5R5 PAG-2 TMEA W-1 addition A1/B1 = HR-40 6/4 (30 mg)  6 R6 PAG-2 TMEAW-2 addition A1/B1 = HR-41 6/4 (30 mg)  7 R4 PAG-4 DIA W-2 additionA1/A3 = HR-28 95/5 (30 mg)  8 R4 PAG-2 DIA W-1 TC A1/A3 = HR-50 95/5

The brevity codes used in the table represents the followings.

[Photoacid Generator]

PAG-1: Ph₃S⁺C₃F₇SO₃ ⁻

PAG-2: Ph₃S⁺C₄F₉SO₃ ⁻

[Basic Compound]

DIA: 2,6-diisopropylaniline,

TBAH: tetrabutylammonium hydroxide,

TMEA: tris(methoxyethoxyethyl)amine, and

PEA: N-phenyldiethanolamine.

[Surfactant]

W-1: Megafac F176 (produced by Dainippon Ink & Chemicals, Inc.;fluorinated)

W-2: Megafac R08 (produced by Dainippon Ink & Chemicals, Inc.;fluorinated and siliconized),

W-3: Troy Sol S-366 (produced by Troy Chemical Co., Ltd.),

W-4: PF656 (produced by OMNOVA; fluorinated), and

W-5: PF6320 (produced by OMNOVA; fluorinated).

[Solvent]

A1: propylene glycol monomethyl ether acetate,

A2: cyclohexanone,

A3: γ-butyrolactone,

B1: propylene glycol monomethyl ether, and

B2: ethyl lactate.

(Exposure Condition: ArF Liquid Immersion Exposure)

An organic anti-reflection film ARC29SR (produced by Nissan ChemicalIndustries, Ltd.) was applied onto a silicon wafer and baked at 205° C.for 60 seconds, thereby forming a 95-nm-thick anti-reflection film. Eachof the above prepared actinic ray-sensitive or radiation-sensitive resincompositions was applied thereonto and baked at 85° C. for 60 seconds,thereby forming a 100-nm-thick resist film. The resultant wafer wasexposed through a 6% half-tone mask of 50 nm 1/1 line and space patternby means of an ArF excimer laser liquid immersion scanner (manufacturedby ASML, XT-1700Fi, NA1.20, σ₀/σ₁=0.94/0.74). Ultrapure water was usedas the liquid for liquid immersion. Thereafter, the exposed wafer washeated at 90° C. for 60 seconds, developed with an aqueous solution oftetramethylammonium hydroxide (2.38 mass %) for 30 seconds, rinsed withpure water, and spin dried to obtain a resist pattern.

(Measurement of Exposure Latitude [EL])

A formed pattern was observed by means of an SEM (eCD2, manufactured byKLA Tencor). The exposure intensity Emax for reproduction of 45 nm,optimum exposure intensity Eopt for reproduction of 50 nm, and exposureintensity Emin for reproduction of 55 nm were measured. The exposurelatitude was calculated by the formula:

[Exposure latitude (%)]=100×(Emax−Emin)/Eopt.

(Measurement of Mask Error Enhancement Factor [MEEF])

Exposure was carried out through not only a line/space=50 nm/50 nm maskpattern but also line/space=47 nm/53 nm, 48 nm/52 nm, 49 nm/51 nm, 51nm/49 nm, 52 nm/48 nm and 53 nm/47 nm mask patterns. Upon patternformation, the line widths were measured by means of an SEM (eCD2,manufactured by KLA Tencor). A graph indicating the mask line widths onthe axis of abscissas and indicating the measured line widths on theordinate axis was drawn, and the gradient of a line resulting fromfirst-order approximation of measurement points (viz. MEEF) wasdetermined.

(Measurement of Line Width Roughness [LWR])

The line-width measurement at 50 points was conducted with respect to a50-nm 1/1 line/space pattern and the 3σ value thereof (viz. LWR) wascomputed.

TABLE 4 Resin LWR EL (A) (nm) (%) MEEF Example 1 (1) 6.4 15.5 4.7 2 (2)6.0 15 5.7 3 (3) 7.0 14 6.9 4 (4) 5.5 16 4.1 5 (5) 5.6 16 4.0 6 (6) 6.614.5 6.2 7 (7) 6.2 15 5.1 8 (8) 6.6 14.5 5.8 9 (9) 6.8 14 6.2 10  (4)5.5 15.8 4.3 11  (4) 5.5 16 4.1 12  (1) 5.3 15.5 4.6 13  (7) 6.0 15.15.1 14  (8) 5.3 16.0 4.2 15  (1) 5.3 16.0 4.2 16  (1) 6.1 15.2 4.5 17 (4) 6.2 15.3 4.4 18  (3) 6.0 15.1 4.1 19  (1) 6.0 15.3 4.5 20  (1) 5.415.7 4.4 Comparative Example 1 R1 9.9 10 10 2 R2 8.9 10 10 3 R3 8.5 9.511 4 R4 8.3 10 10 5 R5 8.7 11 9.5 6 R6 8.3 12 9.1 7 R4 8.8 12 9 8 R4 8.510 10

As apparent from the results given in Table 4, the patterns formed usingthe actinic ray-sensitive or radiation-sensitive resin compositionsaccording to the present invention are superior in all of the LWR,exposure latitude and MEEF, thereby proving that the actinicray-sensitive or radiation-sensitive resin compositions according to thepresent invention can be appropriately used in an ArF liquid immersionexposure process.

The same experiment as described above was carried out except that theexposure condition was changed from the ArF liquid immersion exposure toan ArF dry exposure. As a result, similar patterns excelling in all ofthe LWR, exposure latitude and MEEF were obtained, thereby proving thatthe actinic ray-sensitive or radiation-sensitive resin compositionsaccording to the present invention can also be appropriately used in anArF dry exposure process.

1. An actinic ray-sensitive or radiation-sensitive resin compositioncomprising: (A) a resin having at least two of repeating unitsrepresented by general formula (1) below and exhibiting increasedsolubility in an alkali developer when acted on by an acid; and (B) acompound that generates an acid when exposed to actinic rays orradiation;

wherein: R represents a hydrogen atom or an optionally substituted alkylgroup; A represents:

R₀, each independently in the presence of two or more groups, representsan optionally substituted alkylene group, an optionally substitutedcycloalkylene group or a combination thereof, with the proviso that analkylene group having two or more carbon atoms is excluded when Lrepresents a butyrolactone; Z, each independently in the presence of twoor more groups, represents an ether bond, an ester bond, an amido bond,a urethane bond or a urea bond; L represents a substituent with alactone structure; and n represents the number of repetitions and is aninteger of 1 to
 5. 2. The composition according to claim 1, wherein theresin (A) has at least one of repeating units represented by generalformula (1-1) below as the repeating unit represented by the generalformula (1);

wherein: R, A, R₀, Z and n are as defined above with respect to thegeneral formula (1) of claim 1; R₁, each independently in the presenceof two or more groups, represents an optionally substituted alkyl group,an optionally substituted cycloalkyl group, an optionally substitutedester group, a cyano group, a hydroxy group or an alkoxy group, andprovided that two or more R₁s are present, two thereof may be bonded toeach other to form a ring; X represents an alkylene group, an oxygenatom or a sulfur atom; and m represents the number of substituents andis an integer of 0 to
 5. 3. The composition according to claim 2,wherein the resin (A) has at least two of the repeating unitsrepresented by the general formula (1-1).
 4. The composition accordingto claim 1, wherein each of the at least two of the repeating unitsrepresented by the general formula (1) has different rates of alkalihydrolysis.
 5. The composition according to claim 1, wherein a glasstransition point of the resin (A) is within the range of 130° C. to 170°C.
 6. The composition according to claim 1, wherein the resin (A) hasboth at least one repeating unit having any of groups represented bygeneral formula (2-1) below and at least one repeating unit having anyof groups represented by general formula (2-2) below;

wherein: in the general formula (2-1), each of R₂s independentlyrepresents an optionally substituted alkyl group or an optionallysubstituted monocyclic alkyl group, with the proviso that at least oneof the R₂s is an optionally substituted monocyclic alkyl group, andprovided that when all of the R₂s are alkyl groups, two R₂s are bondedto each other to form a monocyclic alkyl group; and in the generalformula (2-2), each of R₃s independently represents an optionallysubstituted alkyl group or an optionally substituted polycyclic alkylgroup, with the proviso that at least one of the R₃s is an optionallysubstituted polycyclic alkyl group, and provided that when all of theR₃s are optionally substituted alkyl groups, two R₃s are bonded to eachother to form a polycyclic alkyl group.
 7. The composition according toclaim 1, containing any of compounds represented by general formula (I)below as the compound (B);

wherein X⁺ represents a sulfonium or an iodonium, and R represents ahydrogen atom or a substituent having one or more carbon atoms.
 8. Thecomposition according to claim 1, further comprising (C) a hydrophobicresin.
 9. A method of forming a pattern, comprising: forming thecomposition according to claim 1 into a film, exposing the obtainedfilm, and developing the exposed film.